[Effects of specimen preservation and transportation on blood paraquat concentration in rats]

Objective: To investigate the effects of duration, temperature and shake on paraquat (PQ) concentration in the blood of PQ-exposed rats during the specinen preservation and transportation. Methods: In March 2021, 60 SD male rats of Specific Pathogen Free class were randomly divided into low-dose group (10 mg/kg PQ) and high-dose group (80 mg/kg PQ). Each group was divided into 5 subgroups (normal temperature group, cold storage group, 37 ℃ storage group, shaking on normal temperature group and shaking on 37 ℃ group), six rats in each subgroup. The rats were given intraperitoneal injection of PQ, 1 h after exposure, the blood samples were obtained by cardiac extraction. After different interventions, the concentrations of PQ were detected and compared before and after the intervention in each subgroup. Results: In the shaking on 37 ℃ group, the results of PQ concentrations in PQ-exposed rats were significantly lower than those before the intervention (P<0.05). In the other subgroups, the results were not significantly different compared with before intervention (P>0.05) . Conclusion: The concentration of PQ in the blood of rats exposed to PQ was decreased by shaking for 4 hours at 37 ℃.

[Research progress of diabetic corneal neuropathy]

Diabetic neuropathy is a common complication of diabetes. Its incidence among diabetic patients is more than 50%, and its ocular manifestations include diabetic retinopathy and diabetic corneal neuropathy. By using confocal microscopy, diabetic neuropathy in the cornea has been found to occur earlier than other parts of the body, which helps for early diagnosis, risk assessment and treatment options for diabetic peripheral neuropathy. The repair and treatment of nerve damage in diabetic corneal neuropathy has been frequently studied. This review focuses on the research progress of diabetic corneal neuropathy in recent years, and discusses the research findings on corneal nerve injury, anatomical and functional changes, and mechanism of injury and repair. (Chin J Ophthalmol, 2021, 57: 630-636).

[Deep learning based lesion detection from anterior segment optical coherence tomography images and its application in the diagnosis of keratoconus]

Objective: To developed an image analysis system of anterior segment optical coherence tomography (AS-OCT) examination results based on deep learning technology, and to evaluate its effect in identifying various types of corneal pathologies and quantified indices. Methods: A total of 4 026 patients (5 617 eyes), including 1 977 males and 2 049 females, aged (45±23) years, were enrolled in Qingdao Eye Hospital from January 2011 to August 2019. The AS-OCT images were used as a training dataset, which were labeled with location information of 16 corneal pathologies (including corneal epithelial defect, corneal epithelial thickening, corneal thinning and so on) by clinical experts, as well as the tissue stratification of the corneal epithelium and stroma. The labeled AS-OCT images were used to train the corneal pathology detection model and corneal stratification model based on deep convolutional neural network algorithm. Then 1 709 AS-OCT images of the affected eyes were collected as a validation dataset. Compared with the artificial labeling results, the accuracy, sensitivity and specificity were evaluated in the corneal pathology detection model, and the overlapping rate (Dice coefficient) between the labeled area of the model and the artificial labeling area was used to evaluate the corneal stratification model. Results: The results of 5 617 training sets showed that there were 1 472 cases of corneal epithelial defect, 2 416 cases of corneal epithelial thickening, 2 001 cases of corneal thinning, 780 cases of corneal lordosis, 2 064 cases of corneal thickening, 358 cases of subepithelial blisters, 486 cases of subepithelial opacity, 1 010 cases of corneal ulcer, 3 635 cases of stromal opacity, 1 060 cases of posterior elastic layer fold, 137 cases of posterior elastic layer detachment, 665 cases of keratic precipitate, 176 cases of corneal perforation, 127 cases of corneal foreign body, 299 cases of after lamellar keratoplasty (LKP) and 234 cases of after penetrating keratoplasty (PKP). Among 1 709 images, 1 596 were manually labeled. The average sensitivity and specificity of the corneal pathology detection model were 96.5% and 96.1% compared with the results of manual labeling. Fifteen samples were missed for detection, and the rate was 0.93%. The average Dice coefficients of the corneal stratification model for the corneal epithelium and stroma were 0.985 and 0.917, respectively. Conclusions: Our artificial intelligence-based diagnosis system with AS-OCT is able to give quantified information and location information of corneal lesions with high accuracy, which can help ophthalmologists improve the efficiency and accuracy of diagnosis. (Chin J Ophthalmol, 2021, 57: 447-453).

[Clinical observation of ocular injury caused by chestnut burr]

Objective: To analyze the clinical characteristics and treatment of ocular injury caused by chestnut burr. Methods: Retrospective case series study. Data of 48 patients (48 eyes) with ocular injuries caused by chestnut burrs hospitalized in Qingdao Eye Hospital were collected from January 2013 to March 2019. All patients were followed up for at least 3 months. The time of seeking medical advice, lesion region, and characteristics and treatment methods were analyzed. Results: There were 48 patients, including 33 males and 15 females, aged 19 to 74 years [mean, (56±10) years]. The time of injury was late September (25 cases) and early October (23 cases). The shortest time to visit our hospital was 3 hours after injury, and the longest was 8 months after injury. There were 13 cases (27.1%, 13/48) with corneal and/or scleral foreign bodies. All patients were treated with corneal or scleral foreign body extraction. Twenty-four patients (50.0%, 24/48) developed fungal keratitis. Among them, 18 patients had a corneal ulcer, and the infection involved the superficial or full-thickness corneal layer. Six patients had no corneal ulcer, and the infection involved the deep stroma and corneal endothelial surface. The positive rate of fungal examination by confocal microscopy was 87.5% (21/24). Antifungal drugs (2 cases), corneal debridement (5 cases), conjunctival flap covering (2 cases), corneal stroma injection (1 case), and penetrating keratoplasty(14 cases) were given according to the depth of fungal infection. Most of the pathogens were Alternaria spp. Eleven patients (22.9%, 11/48) with necrotizing scleritis were treated with exploration of the sclera. Three patients had scleral foreign body residues on ultrasound biomicroscopy examination, which were removed by operation. Four patients were found to have fungi at the necrotic site of the sclera. Conclusions: The main types of ocular injuries caused by chestnut burrs are corneal and/or scleral foreign bodies, fungal keratitis, and necrotizing scleritis. Chestnut burr foreign bodies should be removed as soon as possible. In the case of fungal keratitis, a drug or surgical intervention should be carried out as early as possible. Necrotizing scleritis is often induced by long-term foreign body retention. Scleral incision and exploration is an effective form of treatment. (Chin J Ophthalmol, 2020, 56: 370-375).

[A clinical analysis of 1 414 cases of fungal keratitis]

Objective: To discuss clinical features and treatments of fungal keratitis, and to provide statistical data for clinical therapy and increase the therapeutic effects. Methods: This is a retrospective case series study. An analysis was performed by collecting patients' demography features, risk factors, onset time, lab results, clinical features and treatment from 1 414 cases of fungal keratitis from January 2006 to October 2016 in Qingdao Eye Hospital, Shandong Eye Institute. Results: In the 1 414 cases (1 414 patients), 1 174 patients (83.0%) came from different areas in Shandong Province, and the rest mainly from provinces on the north of Yangtze River. The age was 40 to 60 years in 874 cases (61.4%). The onset time was often in autumn and winter. The average duration between the onset and treatment was 1 to 74 days; 942 patients (67.1%) visited our hospital in 8-30 days after the appearance of the symptoms. Corneal trauma was the most common risk factor, especially injury by plants (367 cases, 26.4%). The positive rate of direct microscopic examination of potassium hydroxide wet mounts was 96.4%. The positive rate of confocal microscopy was 89.8%. Fungi were detected in corneal ulcer scrapings and (or) diseased corneal tissues obtained during surgery from 973 patients (68.8%). Most of the fungi were Fusarium (595 cases, 61.1%), followed by Alternaria (184 cases, 18.9%) and Aspergillus (119 cases, 12.2%). There were 603 cases (42.7%) of superficial and middle stromal infiltration, 614 cases (43.4%) of deep stromal infiltration and 197 cases (13.9%) of full-thickness corneal infiltration. Diameters of the corneal ulcer lesion were mostly between 4 and 6 mm (725 cases, 51.6%), followed by<3 mm (372 cases, 26.4%) and>6 mm (302 cases, 22.0%). Hypopyon was combined in 498 cases (35.2%), corneal perforation in 34 cases (2.4%), and endophthalmitis in 58 cases (4.1%). Surgery was performed in 1 198 cases (84.8%), including penetrating keratoplasty in 416 cases (29.4%), lamellar keratoplasty in 199 cases (14.1%), and corneal ulcer debridement in 532 cases (37.6%), with an effective rate of 98.1% (408 cases), 97.0% (193 cases) and 92.8% (494 cases), respectively. Two hundred and fifteen cases (15.2%) were treated with medical therapy alone, of which 147 cases (68.4%) were cured. Fifty-six patients (3.9%) finally lost their eye balls, including 54 cases of evisceration and 2 cases of ophthalmectomy. Conclusions: Fusarium is the main causative agent of fungal keratitis in Shandong Province. Direct microscopic examination of potassium hydroxide wet mounts is a simple, rapid and effective test method. Early diagnosis can be made if the result of corneal ulcer scraping examination is positive. Antifungal drug treatments can be done in early onset time. If the drug efficacy is poor or the patient's condition gets worse, immediate surgery is the key to controlling fungal keratitis. (Chin J Ophthalmol, 2020, 56:286-293).

[Surgical treatment of keratoglobus: key techniques of bridge-shaped flap penetrating keratoplasty and whole lamellar keratoplasty with corneoscleral limbal]

Objective: Introduce the surgical techniques of bridge-shaped flap penetrating keratoplasty and whole lamellar keratoplasty with corneoscleral limbal and the comparison of therapeutic effects on keratoglobus. Methods: Five patients (eight eyes) with keratoglobus from January 2010 to December 2015 were included. Three eyes received bridge-shaped flap penetrating keratoplasty (two eyes with corneal penetrating injury due to trauma, one eye with descemet's membrane detachment) and five eyes received whole lamellar keratoplasty with corneoscleral limbal. Results: The patients (four male, one female) aged 3 to 67 years old. Three younger patients were complicated with blue sclera. The visual acuity of all the patients pre-operation were lower than 0.05. The average visual acuity after whole lamellar keratoplasty (LKP) surgery was 0.2, while the average visual acuity after bridge-shaped flap penetrating keratoplasty (PKP) was 0.5. The corneal epithelium of the three eyes received bridge-shaped flap PKP surgery was completely healed within a week with no recurrence of corneal epithelial defect. Whereas one eye after whole LKP surgery arised persistent corneal epithelial defect and healed after blepharorrhaphy. The corneal epithelial of another eye after whole LKP surgery healed slowly and was completely healed after wearing a bandage lens on corneal for 2 months. The corneal epithelial of the remaining three eyes after whole LKP surgery was completely healed within a week. Two eyes received bridge-shaped flap PKP surgery arised corneal graft rejection 2 months after operation and recovered after anti-rejection treatment. No corneal graft rejection arised in the patients receiving whole LKP surgery. Conclusions: The whole lamellar keratoplasty with corneoscleral limbal could effectively reinforce corneal, avoid corneal penetrating injury caused by minor trauma, and improve visual acuity in keratoglobus whose corneas were gradually thinning and corrected vision cannot be improved. The patients with corneal perforating injury or descemet's membrane detachment could obtain good visual prognosis receiving bridge-shaped flap penetrating keratoplasty. (Chin J Ophthalmol, 2019, 55:916-922).

[Effect of different concentrations of Gegen Qinlian decoction on expression of P-glycoprotein and multi-drug resistance protein transporter in Caco-2 cells]

To investigate the effects of Gegen Qinlian decoction on the expression of P-glycoprotein (P-gp) and multi-drug resistance protein (MRP) in epithelial cells of human colon adenocarcinoma Caco-2 cells．The effects of different concentrations of Gegen Qinlian decoction on the expression levels of p-gp and MRP1-6 mRNA in Caco-2 cells were detected by real time quantitative reverse transcriptase PCR (qRT-PCR).12 h after drug treatment (5.00 g·L⁻¹), the expression levels of MDR1 and MRP1-6 were significantly down-regulated at concentration of 5.00 g·L⁻¹; the mRNA expression levels of MDR1，MRP1，MRP2，MRP4，MRP5 and MRP6 were significantly down-regulated at concentration of 2.50 g·L⁻¹; only the expression levels of MRP2 and MRP5 were significantly affected at concentration of 1.00 g·L⁻¹. The results showed that the expression levels of MDR1 and MRP1-6 mRNA in Caco-2 cells could be down-regulated in a dose-dependent manner. Gegen Qinlian decoction may reduce drug efflux by down-regulating the mRNA expression of cell transporters in Caco-2 cell, and increase the time of drug action, thereby enhancing the bioavailability of chemotherapeutic drugs.

[Clinical features, treatment distribution and outcomes of Mooren's ulcer]

Objective: To investigate the clinical features, treatment distribution and transition of Mooren's ulcer, and to observe the clinical outcomes and recurrence. Methods: Retrospective series case study. Medical records of 125 patients (154 eyes) with Mooren's ulcer treated between January 1996 and December 2015 at our hospital were retrospectively reviewed. Seventy-eight males and 47 females were include, with age of (47.6±14.3) years (range: 23-82 years) and median disease course of 6 months (range: 1-240 months). Follow-up occurred between 4.5 and 122 months and the ratio of males to females was 1.66∶1. All patients were divided into two groups: group 1996-2005 and group 2006-2015. Chi-square test was used to analyze the difference of treatment distribution between the two groups and recurrence rate relative to different risk factors. Clinical features and treatment outcomes of Mooren's ulcers were observed simultaneously. Results: The lesion of the primary Mooren's ulcer involved nasal, temporal, superior, inferior and all limbus in 48, 41, 13, 23 and 29 eyes, respectively. The numbers of eyes treated with medical therapy, LKP and amniotic membrane grafting were 6, 61 and 1 in group 1996, with recurrence rate of 1/6, 24.59% and 0 respectively. The numbers in group 2006 were 27, 38 and 14 with recurrence rate of 7.41%, 34.21% and 2/14, respectively. The differences of eyes underwent three different therapies were statistical significance between two groups (χ(2)=29.315, P=0.000), but the differences of total recurrence rate were not (χ(2)=0.149, P=0.699). Thirty-four patients (34 eyes) suffered ulcer recurrence, among which 23 eyes (67.65%) had recurrence within 12 months after treatment and 31 eyes (91.12%) were saved. Finally, 150 of 154 eyes (97.40%) were saved and 129 eyes (83.77%) retained vision better than 0.05. Conclusions: Mooren's ulcers were prone to occur in males and in patients older than 35 years. The lesion more often involved interpalpebral limbus. Lamellar keratoplasty was the most frequently used surgical intervention for primary Mooren's ulcer with a recurrence rate of 28.28%. In recent 10 years, the percentage of patients treated with LKP decreased while percentage of medical treatment and amniotic membrane grafting went up obviously, and the total recurrence rate between two groups had no statitical differences. (Chin J Ophthalmol, 2019, 55:127-133).

[Biopharmaceutics classification system of Chinese materia medica of berberine in Gegen Qinlian decoction]

One of the top-level researches of biopharmaceutics classification system of Chinese materia medica (CMMBCS) is the study on single component in compound Chinese medicine. The medicines shall be classified according to its solubility and intestinal permeability, as well as the ascending degree in multicomponent environment. Based on above, we chose berberine as the main object to explore the change rules of its solubility and intestinal permeability in Gegen Qinlian decoction. Shaking flask-HPLC was used to detect the solubility changes of berberine in compounds. The qualitative investigation of berberine in intestinal absorption was measured by everted gut sac, and the quantitative research of berberine in intestinal absorption was measured by single-pass intestinal perfusion experiment, while the qualitative and quantitative research of berberine absorption into blood was measured by in intestinal perfusion with venous sampling experiment.

[Validation of in situ single pass perfusion model based on P-gp]

To validate in situ rats intestinal single pass perfusion model based on P-glycoprotein (P-gp). Firstly, phenol red perfusion was carried out to verify the close connection structure of intestinal epithelial cells, and the integrity of the intestinal epithelium, with a gravimetric method for correcting water flux. The level of phenol red was determined by high performance liquid chromatography (HPLC) both before and after perfusion. Secondly, the positive drug digoxin specified by FDA was used to validate the model. After different mass concentrations of verapamil were given in the rats, the absorption parameters of digoxin in ileum of rats were observed and compared. The results showed that the phenol red was absorbed in rats ileum segment, with an effective permeability coefficient of (1.09±0.62)×10 ⁻⁶ cm•s ⁻¹. The experiment results indicated that the close connection structure of intestinal epithelial cells was normal, and the integrity of the intestinal epithelium was maintained well. In digoxin perfusion experiment, in case no verapamil was given, digoxin showed certain degree of absorption in rat ileum, with an effective permeability coefficient (Peff) of (1.07±0.59)×10 ⁻⁵ cm•s ⁻¹; after mass concentrations of 0.01,0.1 mmol•L ⁻¹ verapamil were given, the absorption of digoxin was on the rise in rat ileum, with an effective permeability coefficient Peff of (1.58±0.69)×10 ⁻⁵, (3.28±0.95)×10 ⁻⁵ cm•s ⁻¹ respectively (P<0.05). Digoxin perfusion experiment verified that P-gp expression in small intestine epithelium was intact and can be used in the research of P-gp efflux transporter.

[Influence factors of dislocation after bipolar prosthetic replacement]

OBJECTIVE

To discuss the influence factors of dislocation after bipolar prosthetic replacement.

METHODS

A total of 374 patients who received bipolar prosthetic replacement in our hospital from October 2001 to October 2015 were retrospectively studied. The clinic data of patients with dislocation after operation was summarized to analyze the causes.

RESULTS

Dislocation happened in 12 patients among all the 374 patients.10 cases received manual relocation, 2 cases open relocation. Most of the 12 patients were accompanied with neurological and psychiatric disorders, such as Alzheimer's disease, Parkinson's disease, sequelae of cerebral infarction, etc. Some factors like improper body position caused by these complications were the main influence factors of dislocation.

CONCLUSION

Accompanied with neurological and psychiatric disorders is the important influence factor of dislocation after bipolar prosthetic replacement.

Cyclin D1 G870A gene polymorphism and risk of leukemia and hepatocellular carcinoma: a meta-analysis

Cyclin D1 (CCND1) is a key protein involved in cell-cycle regulation, and the CCND1 G870A polymorphism is associated with many types of malignancy. Studies examining the associations between this G870A polymorphism and susceptibility to leukemia and hepatocellular carcinoma (HCC) have shown inconsistent results. Therefore, we conducted a meta-analysis to clarify these associations. A search of the PubMed database yielded 7 relevant articles: 3 pertaining to leukemia and 4 to HCC. The odds ratios (ORs) from individual studies were pooled using a fixed or random-effect model. A significant association was observed between the CCND1 G870A variant and leukemia under the allele contrast model [P = 0.003, OR = 1.49, 95% confidence interval (CI) = 1.15-1.95], the homozygote contrast model (P = 0.003, OR = 2.30, 95%CI = 1.34-3.96), and the recessive model (P = 0.002, OR = 2.03, 95%CI = 1.29-3.21). A significant association was observed between this variant and HCC under the recessive model (P = 0.0006, OR = 1.62, 95%CI = 1.23-2.14), the dominant model (P = 0.002, OR = 1.59, 95%CI = 1.19-2.14), the homozygote contrast model (P < 0.0001, OR = 2.06, 95%CI = 1.45-2.94), and the allele contrast model (P < 0.0001, OR = 1.43, 95%CI = 1.20-1.69). Our findings suggest that heritable CCND1 status may influence the risk of developing leukemia and HCC, and that more attention should be given to carriers of these susceptibility genes.

Role of monochromatic light on development of cecal tonsil in young broilers

Previously, the different monochromatic lights have been demonstrated to affect splenocyte proliferation and melatonin (MEL) secretion in broilers. The present study was designed to evaluate the effects of different monochromatic lights on the development and immune function of broiler cecal tonsils, and to disclose the mechanisms underlying these phenomena. A total of 185 broilers (P0) including intact, sham-operated, and pinealectomized groups were exposed to blue light (BL), green light (GL), red light (RL), and white light (WL) by a light-emitting diode system for 14 days. Compared with RL groups, the GL in the intact and sham-operated groups showed larger follicle areas (66.70%), higher percentages of proliferating cell nuclear antigen (PCNA)-positive cells (33.33%), increased numbers of IgA(+) cells (48.60%), and increased antioxidase activity (33.33%-61.37%), whereas, the density of iNOS and MDA content in GL were lower (43.63%-54.43%) than that of RL. In contrast, after pinealectomy, the area of follicles, the percentage of PCNA-positive cells, the number of IgA(+) cells, and the antioxidase activity decreased in the different light treatments, but the density of iNOS and MDA content increased substantially. There was no significant difference in these parameters between broilers exposed to GL and other lights (P = 0.085-1.000). The results suggested that the enhanced effects of GL on the development and immune function of cecal tonsils in young broilers were mediated by elevated antioxidative status via up-regulation of MEL.

Tumor necrosis factor alpha increases epithelial barrier permeability by disrupting tight junctions in Caco-2 cells

The objectives of this study were to determine the effect of tumor necrosis factor alpha (TNF-alpha) on intestinal epithelial cell permeability and the expression of tight junction proteins. Caco-2 cells were plated onto Transwell microporous filters and treated with TNF-alpha (10 or 100 ng/mL) for 0, 4, 8, 16, or 24 h. The transepithelial electrical resistance and the mucosal-to-serosal flux rates of the established paracellular marker Lucifer yellow were measured in filter-grown monolayers of Caco-2 intestinal cells. The localization and expression of the tight junction protein occludin were detected by immunofluorescence and Western blot analysis, respectively. SYBR-Green-based real-time PCR was used to measure the expression of occludin mRNA. TNF-alpha treatment produced concentration- and time-dependent decreases in Caco-2 transepithelial resistance and increases in transepithelial permeability to the paracellular marker Lucifer yellow. Western blot results indicated that TNF-alpha decreased the expression of phosphorylated occludin in detergent-insoluble fractions but did not affect the expression of non-phosphorylated occludin protein. Real-time RT-PCR data showed that TNF-alpha did not affect the expression of occludin mRNA. Taken together, our data demonstrate that TNF-alpha increases Caco-2 monolayer permeability, decreases occludin protein expression and disturbs intercellular junctions.

Neuroepithelial stem cells differentiate into neuronal phenotypes and improve intestinal motility recovery after transplantation in the aganglionic colon of the rat

The purpose of this study was to elucidate the possibility and the biological significance of intracolonic grafting of neuroepithelial stem cells (NESCs) as a therapeutic strategy for neuronal replacement in disorders of the enteric nervous system (ENS) such as aganglionosis. The enteric plexus of rat colon were eliminated by serosal application of the cationic surfactant benzalkonium chloride. NESCs were harvested from the neural tube of embryonic rat, labelled with bromodeoxyuridine (BrdU), and transplanted into the denervated colon. After 2, 4 and 8 weeks, grafted cells were visualized in colon sections by fluorescent double-staining for BrdU and neuronal, astrocytic, neurochemical or stem cell markers. Eight weeks post-transplantation, the intestinal motility was assessed by measuring the changes of intraluminal pressure responding to inflating stimulation and the responses to electrical field stimulation (EFS). Our results indicate that when transplanted into the denervated gut, NESCs survived and could differentiate into neurons and glial cells in vivo. Furthermore, inflation stimulated contraction and EFS-induced response were observed in NESCs grafted group compared with no reaction in denervated group. Therefore, NESCs can survive and function in the denervated rat colon in vivo, which indicates that NESCs provide a promising cellular replacement candidate for ENS.

Changes in the expression of calcitonin receptor-like receptor, receptor activity-modifying protein (RAMP) 1, RAMP2, and RAMP3 in rat uterus during pregnancy, labor, and by steroid hormone treatments

Calcitonin gene-related peptide (CGRP) and its related peptide, adrenomedullin (AM), are potent smooth muscle relaxants in a variety of tissues. The CGRP has been reported to play an important role in maintaining uterine relaxation during pregnancy. We have previously reported that CGRP-induced uterine relaxation was gestationally regulated. Calcitonin receptor-like receptor (CRLR), a seven-domain transmembrane protein functions as CGRP-A receptor, in association with receptor activity-modifying protein (RAMP) 1, a single-domain transmembrane protein, whereas CRLR and RAMP2 or RAMP3 constitute a receptor for AM. In the present investigation, we examined the mRNA expression of CRLR, RAMP1, RAMP2, and RAMP3 in rat uterus (n = 8) by reverse transcriptional analysis and polymerase chain reaction to assess the changes in the expression of CGRP-A- and AM-receptor components during pregnancy and labor and by steroid hormone treatments in adult ovariectomized rats. The changes in mRNA are expressed relative to the 18S mRNA in the uterus of rats at various stages: nonpregnant, pregnant on Day 18, spontaneous labor at term, Day 2 postpartum, and in pregnant rats on treatment with RU486. Ovariectomized rats treated for 3 days twice daily s.c. with estradiol-17beta (2.5 microg/injection), progesterone (2 mg/injection), and the combination of estradiol-17beta and progesterone (same doses as above) were also examined for the expression of various receptor components. Results showed that mRNA expression of the receptor components was significantly higher (P < 0.001 for CRLR, P < 0.01 for RAMP1, P < 0.05 for RAMP2, and P < 0.01 for RAMP3) in pregnant compared to nonpregnant rats. Except for RAMP3, expression of all the other three genes decreased significantly (P < 0.05) during labor. A progesterone antagonist, RU486 significantly decreased (P < 0.01 for CRLR, P < 0.05 for RAMP1, RAMP2, and RAMP3) all the receptor components during pregnancy. In adult ovariectomized rats, progesterone caused significant increases in CRLR (P < 0.001), RAMP1 (P < 0.05), and RAMP2 (P < 0.01). Levels of RAMP3 were unaffected by the progesterone treatment. Estradiol-17beta treatment decreased all of the four receptor components significantly (P < 0.01 for CRLR, P < 0.05 for RAMP1, RAMP2, and RAMP3). Our results demonstrate that both CGRP and AM may play a role in uterine quiescence during pregnancy and that their receptor components are regulated by the steroid hormones.

Expression of calcitonin gene-related peptide receptor components, calcitonin receptor-like receptor and receptor activity modifying protein 1, in the rat placenta during pregnancy and their cellular localization

Calcitonin gene-related peptide (CGRP), one of the most potent endogenous vasodilators known, has been implicated in vascular adaptations and placental function during pregnancy. The present study was aimed to investigate mRNA expression of CGRP-A receptor components, calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein 1 (RAMP(1)) in the rat placenta. Immunohistochemical staining of rat placentas obtained on day 18 of pregnancy using polyclonal anti-CRLR and RAMP(1) antibodies revealed that labelling was specifically concentrated in the cytotrophoblast and syncytium in labyrinth, trophoblastic giant cells and basophilic cells in trophospongial cell layer, and endothelium and smooth muscle cells in fetal vessels. The intensity of staining was reduced in all these cells except in the syncytium in placentas obtained during labour. RT-PCR analysis showed that mRNA expression of CRLR and RAMP(1) was significantly higher in the rat placenta from gestation day 17 to day 22, than during labour. During pregnancy, 17beta-estradiol inhibits, while progesterone stimulates, placental mRNA and proteins for CRLR and RAMP(1). Antiestrogen, ICI 182780, increased, whereas antiprogesterone, RU 486, inhibited the expression of both CRLR and RAMP(1). In summary, we demonstrate the presence and cellular localization of CRLR and RAMP(1) in the rat placenta. Elevated placental CRLR and RAMP(1) may be involved in CGRP-related increases in blood flow and therefore fetal growth and decreases at term labour may help minimize the blood loss.

Infusion of pregnant rats with calcitonin gene-related peptide (CGRP)(8-37), a CGRP receptor antagonist, increases blood pressure and fetal mortality and decreases fetal growth

Calcitonin gene-related peptide (CGRP) is the most potent endogenous vasodilatory peptide, and is involved in the regulation of blood flow to vital organs. We have previously shown that CGRP may be involved in vascular adaptations that occur during pregnancy, and that steroid hormones may be involved in these mechanisms. We hypothesized that endogenous CGRP is required for maintaining blood pressure and fetoplacental growth in pregnant rats, and that progesterone will enhance CGRP effects. The vasodilatory effects of CGRP are known to be inhibited by a competitive CGRP receptor antagonist, the C-terminal fragment CGRP(8-37). In the present study, we investigated whether continuous s.c. infusion of CGRP(8-37) to pregnant rats will reduce fetoplacental growth and increase systolic blood pressure. We also assessed whether progesterone will alter the effects of CGRP(8-37) on blood pressure during postpartum. Groups of five pregnant rats were s.c. infused with varying doses of CGRP(8-37) from Day 17 of pregnancy. Daily systolic blood pressures, pup weight, mortality at term delivery, and fetoplacental weights on Day 20 of gestation were measured. CGRP(8-37) at a dose of 0.083 mg day(-1) kg(-1) body weight (BW) showed no effects; however, doses of 0.33 and 1.33 mg day(-1) kg(-1) BW increased (P < 0.05) blood pressure during pregnancy, and these elevated blood pressures persisted during postpartum with the highest dose used. Progesterone (2 mg per injection, twice a day; s.c.) treatment significantly elevated blood pressure in rats infused with CGRP(8-37) during postpartum, suggesting that progesterone regulates CGRP-induced vascular effects. CGRP(8-37) infusion caused significant reductions in pup weight with an increase in mortality rate, and these effects were dose-dependent. Placental and fetal weights were also decreased prior to term on Day 20 of gestation, 72 h after CGRP(8-37) infusion, indicating effects on uteroplacental tissues. Therefore, we suggest that endogenous CGRP plays an important role in maintaining normal fetoplacental development, fetal survival, and vascular adaptations during pregnancy.

Increased nitric oxide synthase activity and expression in the human uterine artery during pregnancy

Evidence exists that NO plays a role in the vasodilation that occurs during pregnancy. The purpose of the present study was to determine whether the role of NO is associated with an increase in the activity and protein expression of NO synthase (NOS) in the human uterine artery. Uterine arteries were obtained from pregnant patients (P arteries) and nonpregnant patients (NP arteries). NOS activity was estimated with the L-[(3)H]-arginine-to-L-[(3)H]-citrulline conversion method and on the basis of changes in tissue levels of cGMP. Western immunoblotting and immunohistochemistry were used to assess NOS protein expression. Ca(2+)-dependent NOS activity was 8 times greater (P:<0.01) in P than in NP arteries. Although most of this pregnancy-induced increase in NOS activity was Ca(2+) dependent (64%), a considerable portion was Ca(2+) independent. Expressions of endothelial NOS (eNOS) and neuronal NOS, but not inducible NOS, were demonstrated in P and NP arteries. The eNOS was located in the endothelium and stained with a qualitative order of P arteries>NP arteries (follicular)>NP arteries (luteal). The neuronal NOS was located in the adventitia of P and NP arteries. Basal NO-dependent and bradykinin-stimulated levels of cGMP were higher (P:<0.05) in P than in NP arteries. These results indicate that an upregulation of eNOS protein expression could account for the increased NO synthesis/release in the human uterine artery during pregnancy.

Estradiol-17beta inhibits nitric oxide synthase (NOS)-II and stimulates NOS-III gene expression in the rat uterus

Nitric oxide (NO) is synthesized by NO synthases (NOS) from L-arginine in a variety of tissues, including rat uterus. Progesterone was shown to be required for maintaining elevated NOS II expression in pregnant rat uterus. However, effects of estrogens on uterine NOS II expression remains unclear. In the present study, we examined whether 17beta-estradiol regulates NO production and NOS II expression in the rat uterus during pregnancy and in nonpregnant rats treated with lipopolysaccharide (LPS). Rats on Day 18 of pregnancy received 17beta-estradiol (0.5 or 5 microgram/rat). Groups of ovariectomized (ovx) rats received 17beta-estradiol (5 microgram/rat) or LPS (1 mg/rat) or a combination of the two or received vehicle only. All rats were sacrificed 24 h after treatments. Nitrite concentrations in uterine cultures were measured by Greiss reaction. Uterine NOS II and NOS III proteins and mRNA levels were determined by Western blotting and reverse transcription polymerase chain reaction, respectively. In the pregnant rat, estradiol administration caused inhibition in total NO production, suppression of both mRNA and protein levels of NOS II enzyme, and increase in NOS III mRNA and protein levels in the uterus in a dose-dependent manner. The data indicate that estradiol inhibits NOS II and total NO generation and stimulates NOS III expression. In ovx rats, LPS stimulated NOS II mRNA and NO production by the uterus. Coadministration of 5 microgram estradiol profoundly suppressed NOS II mRNA and NO generation but elevated NOS III mRNA. Thus, estradiol inhibited LPS-induced increases in NOS II mRNA. Estradiol inhibits NO production by NOS II through the inhibition of NOS II expression in the rat uterus. This inhibition of NOS II expression occurs whether NOS II expression is constitutive (pregnancy) or induced (LPS-treated nonpregnant). Estradiol inhibition of NOS II expression occurs in the presence (pregnancy) or absence (ovx) of progesterone. Estradiol may play a role in regulating NOS II expression and NO production and uterine contractility during pregnancy and labor.

Pregnancy and exogenous steroid treatments modulate the expression of relaxant EP(2) and contractile FP receptors in the rat uterus

Prostaglandins (PGs) interact with specific receptors on plasma membranes to regulate myometrial activity in many species. The present study examined whether the expression of relaxant prostaglandin E receptor subtype two (EP(2)) and contractile prostaglandin F receptor (FP) mRNA in the rat uterus is changed during various states of pregnancy and regulated by steroid hormones. Expression of mRNA for EP(2) and FP receptors in the full-thickness uteri was analyzed by reverse transcription-polymerase chain reaction using specific primers. Abundance of receptor mRNA was expressed relative to beta-actin mRNA. Results showed that 1) mRNA for EP(2) receptors in the rat uterus was substantially increased during pregnancy (320%) compared with the nonpregnant state (100%, P < 0.01), and declined during labor at term (36% vs. 100% in control, P < 0.01); 2) mRNA expression for FP receptors in rat uterus was increased during pregnancy (333% vs. 100% in nonpregnant rats, P < 0. 01) and reached maximal levels during labor (515% vs. 100% in control, P < 0.01); 3) upon RU-486 treatment on Day 19 of pregnancy, uterine EP(2) receptor mRNA levels were decreased (18% vs. 100% in control, P < 0.01), and FP mRNA levels were increased (357% vs. 100% in control, P < 0.01); 4) with ICI 164384 (an antiestrogen) treatment on Day 19 of gestation, uterine FP receptor mRNA levels were decreased without effects on EP(2) receptors; 5) in ovariectomized (ovx) rats, progesterone increased EP(2) (163% vs. 100% in control, P < 0.01) and had no effects on FP receptor mRNA expression in the rat uterus; 6) estradiol increased FP receptor mRNA levels (358% vs. 100% in control, P < 0.01) and had no effects on EP(2) mRNA in the ovx rat uterus. Therefore, we conclude that steroid hormones modulate the mRNA for relaxant EP(2) and contractile FP receptors for PGs in the uterus and thus regulate uterine activity during pregnancy and labor.

Localized increase in nitric oxide production and the expression of nitric oxide synthase isoforms in rat uterus with experimental intrauterine infection

OBJECTIVE

We recently reported that nitric oxide was associated with increased mortality among pregnant rats with intrauterine infection. In our current study we investigated the expression of different isoforms of nitric oxide synthases and nitric oxide in the nonpregnant rat uterus with experimental intrauterine infection.

STUDY DESIGN

Pathogenic Escherichia coli was inoculated into the uterine lumen of ovariectomized rats. Animals were killed after inoculation, and uterine horns were collected for assessing nitric oxide production with high-performance liquid chromatography and nitric oxide synthase (type II and type III) protein expression with Western immunoblotting and immunofluorescence methods.

RESULTS

(1) Nitric oxide production increased in the infected uterine horn in a time-dependent manner after intrauterine infection but did not increase in the uninfected horn. (2) Nitric oxide synthase type III protein contents did not show a difference between infected and uninfected horns, and type III nitric oxide synthase was expressed by the epithelial cells and smooth muscle cells. (3) Type II nitric oxide synthase was abundantly expressed in infected horns but was not expressed in uninfected horns. Immunofluorescence data indicated that macrophages and natural killer cells, located in the endometrial layer clustering around epithelial cells, expressed type II protein.

CONCLUSION

We suggest that localized increase in type II nitric oxide synthase expression and nitric oxide production occurs in response to intrauterine infection and that the nitric oxide system may play a role in host response to restrict the infection.

Involvement of calcitonin gene-related peptide in the modulation of human myometrial contractility during pregnancy

Calcitonin gene-related peptide (CGRP) is a potent vasodilator and relaxes smooth muscle of a variety of tissues, but the effects of CGRP on human myometrial contractions and the changes in CGRP receptors (CGRP-Rs) in human myometrium have not been described. We report that CGRP induced dose-dependent relaxation in spontaneously contracting myometrium from pregnant women. This relaxation effect is diminished in myometrium obtained from patients during labor and in the nonpregnant state. CGRP-induced relaxations are inhibited by a CGRP-R antagonist (CGRP(8-37)), a soluble guanylate cyclase inhibitor (LY(83583)), and a nitric oxide synthase inhibitor (L-NAME). Both Western blotting and mRNA analysis showed that CGRP-Rs are present in human myometrium, and that the expression of these receptors is increased during pregnancy and decreased during term labor. Immunofluorescent staining revealed that CGRP-Rs are abundant in the myometrial cells of pregnant women who are not in labor, and are minimal in uterine specimens from women in labor and in the nonpregnant state. We conclude that increased CGRP-Rs in myometrium, and resulting enhanced myometrial sensitivity to CGRP, may play a role in maintaining human myometrium in a quiescent state during pregnancy, and that a decline in the CGRP-Rs at term could contribute to the initiation of labor.

Nitric oxide reverses prostaglandin-induced inhibition in ovarian progesterone secretion in rats

The present studies were undertaken to determine whether nitric oxide (NO) is involved in the regulation of ovarian progesterone and oestradiol secretion in rats. Immature female Sprague-Dawley rats at 27 days of age were injected s.c. with 4 IU pregnant mare's serum gonadotrophin (PMSG) and were killed 72 h after the injection. The ovaries were collected, weighed and cultured in Dulbecco's modified Eagle's medium containing saline, NO donor, NO synthesis inhibitor or prostaglandin F2 alpha (PGF2 alpha). After 24 h culture, the medium concentrations of progesterone and oestradiol were measured by radioimmunoassay. Results showed that: (i) diethylenetriamine (DETA)/NO (1 x 10(-6), 1 x 10(-5), 1 x 10(-4) M), an NO donor, caused a dose-dependent increase in progesterone synthesis (355 +/- 43, 443 +/- 46, 647 +/- 55 ng/g ovary respectively, P < 0.01) with a concomitant decrease in ovarian oestradiol secretion (408.1 +/- 50.7, 272.9 +/- 28.2, 132.6 +/- 34.6 pg/g ovary respectively, P < 0.01); (ii) neither progesterone nor oestradiol concentrations in the culture medium were altered by DETA without NO; (iii) NG-nitro-l-arginine methyl ester (1 x 10(-4) M), an inhibitor of NO synthesis, did not significantly affect progesterone and oestradiol secretion by rat ovaries; (iv) PGF2 alpha(1 x 10(-6) M) caused a fall in progesterone and oestradiol synthesis; (v) co-incubation with DETA/NO, significantly reversed the PGF2 alpha-induced decrease in progesterone concentrations from 184 +/- 29 to 388 +/- 60 ng/g (P < 0.01), but not that of oestradiol. It can be concluded that NO up-regulates progesterone secretion and down-regulates oestradiol secretion in rat ovaries, and NO can reverse PGF2 alpha-induced inhibition in ovarian progesterone secretion.

Regulation of inducible nitric oxide synthase messenger ribonucleic acid expression in pregnant rat uterus

Nitric oxide synthases catalyze the synthesis of the biomediator, nitric oxide, from L-arginine in a variety of tissues. The expression and regulation of inducible isoform of nitric oxide synthase (NOS II) in the uterus were assessed in this study by reverse transcription-polymerase chain reaction with the use of specific primers. Results showed the following: 1) NOS II mRNA expression in the rat uterus was substantially increased during pregnancy and decreased during labor at term; 2) RU-486 (an antagonist of progesterone) induced preterm labor and was associated with a marked decrease in NOS II mRNA expression to 60.9%, 20.3%, and 2.9% at, respectively, 6, 12, and 24 h after treatment compared with the control value (100%); 3) progesterone administration in pregnant rats significantly increased uterine NOS II gene expression (374.1% vs. 100%); 4) NOS II mRNA in the uterus was significantly reduced by prostaglandin F2alpha (PGF2alpha; 11.6% vs. 100% in control); 5) treatment with progesterone prevented PGF2alpha-induced inhibition in NOS II mRNA expression; 6) ICI 164384, an antiestrogen, significantly increased serum progesterone concentration and stimulated NOS II expression by the uterus in a time-dependent manner; 7) as shown by immunofluorescent studies, cells stained by NOS II antibodies were apparent in the decidual compartment as well as in areas between myometrial cell bundles in the pregnant rat uterus. The density of staining decreased in the specimens at labor and postpartum. We conclude that NOS II gene expression in the rat uterus was enhanced during pregnancy and decreased during labor and postpartum. NOS II in rat uterus is up-regulated by progesterone and down-regulated by estrogens and prostaglandins, consistent with their role in uterine activity regulation during pregnancy and labor.

Uterine relaxation responses to calcitonin gene-related peptide and calcitonin gene-related peptide receptors decreased during labor in rats

OBJECTIVES

Our purpose was to investigate (1) whether uterine relaxation responses to calcitonin gene-related peptide are differentially regulated during pregnancy and labor, (2) the involvement of nitric oxide in smooth muscle relaxant action of calcitonin gene-related peptide in the rat uterus, (3) whether receptors for calcitonin gene-related peptide are expressed in rat uterus, and if so (4) whether the concentrations of these receptors are differently regulated during pregnancy and labor.

STUDY DESIGN

Rats were killed on day 18 of gestation, at the time of spontaneous labor, or postpartum day 2. The uteri were removed for in vitro contractility measurements, nitric oxide production, and calcitonin gene-related peptide receptor binding assay.

RESULTS

(1) Calcitonin gene-related peptide induced a dose-dependent relaxation in spontaneously contracting uterine strips from pregnant rats on day 18 of gestation; (2) the relaxation effects of calcitonin gene-related peptide on the uterus were decreased during spontaneous delivery at term and post partum compared with that during pregnancy; (3) calcitonin gene-related peptide-induced relaxation was inhibited by pretreatment of the uterine tissue with a calcitonin gene-related peptide receptor antagonist, calcitonin gene-related peptide(8-37); (4) nitric oxide synthesis inhibitor (N(G)-nitro-L-arginine methyl ester) and soluble guanylate cyclase inhibitor (LY83583) significantly decreased calcitonin gene-related peptide-induced relaxation of the rat uterus during pregnancy; (5) calcitonin gene-related peptide increased the uterine nitric oxide production in pregnant rats, and this increase was obliterated in the presence of calcitonin gene-related peptide(8-37); and (6) calcitonin gene-related peptide receptors are present in rat uterus, and the concentration of these receptors dramatically increases during pregnancy and decreases during labor at term.

CONCLUSIONS

Calcitonin gene-related peptide inhibits uterine spontaneous contractions in rats during pregnancy but not during labor and post partum. The inhibitory effects of calcitonin gene-related peptide on uterine contractility appear to be modulated, at least in part, by the activation of nitric oxide generation in the rat uterus. Changes in calcitonin gene-related peptide receptors could contribute to the changes in calcitonin gene-related peptide-mediated uterine relaxation during pregnancy and labor.

Immunohistochemical localization of constitutive and inducible cyclo-oxygenases in rat uterus during the oestrous cycle and pregnancy

The uterus is a rich source of eicosanoids synthesized from arachidonic acid metabolism through the cyclo-oxygenase pathway. Two isoforms of cyclo-oxygenase, constitutive (COX-I) and inducible (COX-II) enzyme, have been reported. In the present study, we have immunohistochemically mapped the distribution of both COX-I and COX-II during various physiological states of the rat uterus. Uterine tissue was collected from female rats (a) during different stages of the oestrous cycle, (b) on days 1, 4, 8 and 18 of gestation, (c) after spontaneous delivery and (d) post partum, and fixed in Bouin's fixative. After paraffin wax embedding, 5-microm-thick sections were immunohistochemically stained by the ABC technique. Observation of the stained sections under the light microscope revealed that, in non-pregnant rat uterus, both COX-I and COX-II were abundantly expressed in the endometrium, with minimal staining observed in the myometrium. Staining was more prominent in epithelial cells than in stromal cells. The intensity of staining in epithelial cells was highest at pro-oestrus and oestrus and lowest at dioestrus. In pregnant rats, although the expression of both COX-I and COX-II was localized primarily to the endometrium with very little staining in the myometrium on day 1 of gestation, both of these enzymes were also apparent in myometrial cells by day 4 of gestation. The staining intensity of endometrial and myometrial cells increased further with the progression of gestation, being maximal at the time of spontaneous delivery. During the post-partum period, however, the staining intensity for both of the enzymes in endometrium and myometrium was decreased. Thus, our studies show that the expression of cyclo-oxygenases in various uterine cells vary with the oestrous cycle and with pregnancy. Furthermore, prominent increases in the expression of cyclo-oxygenases in the myometrium during pregnancy and parturition imply that the cyclo-oxygenase system in the myometrium may play a major role in modulating uterine contractility during pregnancy and labour.

Role and regulation of nitric oxide in the uterus during pregnancy and parturition

OBJECTIVE

To review the English-language literature as it relates to the role and regulation of uterine nitric oxide (NO) during pregnancy and parturition, special emphasis being placed on the interactions of NO with other uterotonic agents.

METHODS

A thorough literature review of the English-language literature using a Medline search was performed.

RESULTS

Current data support the view that NO is generated in the uterus and inhibits uterine contractility. Gestation, parturition, steroid hormones, and prostaglandins modulate both the generation and the effects of NO on the uterus. The changes in NO and its effects are consistent with the theory that NO plays a role in uterine quiescence during pregnancy. A change in this system at term or preterm could play a role in inhibition of labor and delivery.

CONCLUSION

Uterine NO may play a role in maintaining uterine quiescence during pregnancy.

Involvement of nitric oxide pathway in prostaglandin F2 alpha-induced preterm labor in rats

OBJECTIVE

Our purpose was to investigate the roles of nitric oxide and prostaglandins in controlling parturition.

STUDY DESIGN

Pregnant rats on day 18 of gestation were injected intraperitoneally with prostaglandin F2 alpha, prostaglandin F2 alpha plus diethylenetriamine-nitric oxide (a donor of nitric oxide), prostaglandin F2 alpha plus diethylenetriamine without nitric oxide, or vehicle. Uterine nitrite production, nitric oxide synthase messenger ribonucleic acid and contractile response in vitro, and serum progesterone levels were measured. The labor and delivery of the rats also were monitored.

RESULTS

Exogenously administered prostaglandin F2 alpha significantly inhibited nitric oxide production by the uterus in a time-dependent manner with maximal effects observed 48 hours after prostaglandin F2 alpha treatment. Messenger ribonucleic acid for inducible nitric oxide synthase but not endothelial nitric oxide synthase messenger ribonucleic acid in the uterus was significantly inhibited by prostaglandin F2 alpha with maximal inhibition at 48 hours after prostaglandin F2 alpha injection. The serum progesterone concentration was substantially reduced by prostaglandin F2 alpha, and this reduction was partially reversed by administration of diethylenetriamine-nitric oxide but not diethylenetriamine without nitric oxide. Prostaglandin F2 alpha caused increases in contractile activity of the uterus in a dose-dependent manner. Diethylenetriamine-nitric oxide (10(-4) mol/L) blocked prostaglandin F2 alpha-induced contractions. Premature parturition was induced within 48 hours after prostaglandin F2 alpha injection in 100% of the animals. Coadministration of diethylenetriamine-nitric oxide completely prevented the preterm labor induced by prostaglandin F2 alpha.

CONCLUSION

Prostaglandin F2 alpha inhibited inducible nitric oxide synthase messenger ribonucleic acid and subsequent nitric oxide generation in the rat uterus. Nitric oxide can prevent prostaglandin F2 alpha-induced preterm labor, possibly by attenuating the fall in serum progesterone and blocking uterine contractions induced by prostaglandin F2 alpha administration.

Rat myometrial smooth muscle cells express endothelial nitric oxide synthase

We examined if rat myometrial cells in culture generate nitric oxide (NO) and express various isoforms of NO synthase (NOS). Myometrial cells isolated from rats on day 18 of gestation were incubated with various stimulators and inhibitors of NOS for 24 and 48 h, and NO production was evaluated by measuring nitrites in the media and NOS proteins in the cell lysates. NO was produced by myometrial cells and its production inhibited by N(G)-methyl-L-arginine (L-NMMA). This inhibition was reversed by L-arginine (3 mM). Interleukin-1beta (IL-1beta) significantly stimulated NO production, in a dose-dependent manner. The IL-1beta-stimulated NO production was inhibited by the NOS inhibitor, L-NMMA, whose effects were reversed by L-arginine. Abundant NOS III protein was detectable in freshly isolated myometrial cells, and this was maintained in culture in the presence of fetal bovine serum (FBS; 10%). In the absence of FBS, NOS III levels decreased significantly (by 90%) within 24 h. In contrast, NOS I and NOS II proteins were undetectable in freshly isolated muscle cells and in cells cultured without IL-1beta. However, NOS II protein in these cells was induced by IL-1beta. Thus, NO is produced by myometrial cells through the NOS III isoform, and the myometrial NO may be important in maintaining uterine quiescence during pregnancy.

Immunocytochemical localization of nitric oxide synthase-III in reproductive organs of female rats during the oestrous cycle

Constitutive endothelial nitric oxide synthase (NOS III) expression during the oestrous cycle was mapped immunocytochemically on 5 microns-thick paraffin sections of rat female reproductive organs. Ovarian NOS III immunoreactivity increased with follicular maturation (strongest in dioestrus corpora lutea), suggesting that nitric oxide may regulate folliculogenesis and luteal functions. Oviductal NOS III, localized in mucosal epithelium and muscular wall, was maximal during pro-oestrus and oestrus, suggesting that nitric oxide may impart periovulatory quiescence for reception, retention and fertilization of ovulated oocytes. Uterine NOS III, localized in endometrial and glandular epithelium, and in myometrial smooth muscle cells, was abundantly expressed during pro-oestrus and oestrus. The peri-implantation period in pregnant rats corresponds to the periovulatory period and the elevated NOS, and thus nitric oxide may provide uterine relaxation to facilitate embryo implantation following fertilization. Cervical NOS III, localized in the mucus-secreting epithelium and smooth muscle cells, exhibited enzyme abundance during pro-oestrus and oestrus, probably indicating cervical preparation to facilitate sperm entry following mating. Vaginal NOS III, found in the stratified squamous epithelial lining and in smooth muscle cells, was maximal during oestrus and pro-oestrus, suggesting that nitric oxide may stimulate vaginal secretions. Differential expression of NOS III by different reproductive organs during the oestrus cycle suggests a role for nitric oxide in modulating reproduction.

Preterm birth in rats produced by the synergistic action of a nitric oxide inhibitor (NG-nitro-L-arginine methyl ester) and an antiprogestin (onapristone)

OBJECTIVE

The aim of this study was to determine whether inhibition of nitric oxide synthesis would affect the action of an antiprogesterone to provoke preterm labor.

STUDY DESIGN

Pregnant rats were continuously infused with NG-nitro-L-arginine methyl ester starting on day 16 of gestation. On day 17 of gestation groups of animals were injected subcutaneously with a single dose of either 3 or 30 mg/kg onapristone; animals were monitored for preterm labor and delivery for up to 48 hours.

RESULTS

Significant findings included the following results. (1) Combined treatment with NG-nitro-L-arginine methyl ester (50 mg per day) and low-dose onapristone (3 mg/kg) produced preterm labor, > 70% of the fetuses were delivered within 27 hours of treatment, whereas < 5% of the fetuses were delivered in the animals receiving either of these compounds alone. (2) NG-nitro-D-arginine methyl ester (50 mg per day) had no effect. (3) inhibition of nitric oxide by NG-nitro-L-arginine methyl ester also significantly increased the efficacy of high-dose onapristone (30 mg/kg) in preterm labor and delivery.

CONCLUSION

Treatment of pregnant rats with a combination of a nitric oxide inhibitor with onapristone significantly potentiated the ability of the antiprogesterone to induce preterm labor. The interaction of nitric oxide and progesterone may be required to maintain pregnancy.

Nitric oxide synthase isoforms in the rat uterus: differential regulation during pregnancy and labour

Production of nitric oxide in the uterus is increased during pregnancy and decreased during delivery. In this study the isoform of nitric oxide synthase which may be responsible for the changes in nitric oxide production was investigated in relation to pregnancy and delivery. Monoclonal antibodies were used to measure changes in neuronal nitric oxide synthase (NOS I), macrophage nitric oxide synthase (NOS II) and endothelial cell nitric oxide synthase (NOS III) protein in the rat uterus by densitometric scanning of specific bands. Results show that: (1) NOS II protein concentrations in the uterus were substantially increased during pregnancy and were decreased during delivery, both at term and preterm (induced by RU486); (2) NOS III protein was present at all stages examined but the concentrations were unchanged; (3) NOS I was present in the rat uterus during the nonpregnant stage but not during pregnancy and delivery. The changes in uterine NOS II protein concentrations during pregnancy and delivery were further confirmed by the changes in the Ca(2+)-independent, but not Ca(2+)-dependent, nitric oxide synthase activity. Therefore, an increase in NOS II, thus in nitric oxide production during pregnancy, may play a role in maintaining uterine quiescence.

Differential expression of cyclooxygenase-1 and -2 proteins in rat uterus and cervix during the estrous cycle, pregnancy, labor and in myometrial cells

The synthesis of prostaglandins in the uterus at term are modulated by two isoforms of the enzyme cyclooxygenase (COX): constitutive COX-1 and inducible COX-2. This study aims to characterize the expression of the protein for COX-1 and -2 in the rat uterus and cervix during the estrous cycle, pregnancy, and labor, and in cultured myometrial cells. Western immunoblotting of proteins was performed and quantitation of protein was obtained densitometrically. Results indicate: 1) the rat uteri, cervix, and isolated myometrial cells express both COX-1 and COX-2 proteins, 2) during pregnancy, both COX-1 and -2 increase, with a dramatic increase at parturition (250%-280%), 3) a 2-fold increase of cervical COX-2 is seen at spontaneous labor, 4) during proestrus and estrus, uterine expression of COX-2 is elevated, 5) both COX-1 and -2 were expressed by rat myometrial cells and treatment with IL-1 beta (10 ng/mL) produced a significant increase in COX-2, and 6) immunocytochemical studies show that both COX-1 and -2 were primarily localized to the epithelial cells of the endometrium and smooth muscle cells in the circular layers of the myometrium in the uterus and to the epithelial cells and smooth muscle cells in the cervix. Thus, we propose that increased expression of COX-2 may be involved at term in increased uterine contractility and cervical ripening.

Calcitonin gene-related peptide reverses the hypertension and significantly decreases the fetal mortality in pre-eclampsia rats induced by N(G)-nitro-L-arginine methyl ester

We recently established that the chronic inhibition of nitric oxide production with N(G)-nitro-L-arginine methyl ester (L-NAME) increases blood pressure and fetal mortality in pregnant rats. Using this animal model, we have investigated whether calcitonin gene-related peptide (CGRP) can reverse the pre-eclampsia-like conditions produced by L-NAME. CGRP and L-NAME were chronically infused s.c. into pregnant rats separately or together starting on day 17 of gestation; a control group was given saline infusions. Systolic blood pressure was measured on gestational days 17, 18, 19 and 22 and post-partum days 1 and 2. The weight and mortality of the pups were recorded immediately after spontaneous delivery. Animals treated with L-NAME exhibited significant elevations of blood pressure on days 18, 19 and 22 of gestation and during post-partum, increased pup mortality (18.4 versus 0.0%) and decreased pup weights (5.14 +/- 0.07 versus 6.20 +/- 0.06 g). The co-administration of L-NAME and CGRP prevented the gestational (not the post-partum) L-NAME hypertension and decreased pup mortality to 6.4% but did not reverse the decreased fetal weight (5.31 +/- 0.06 g). Our data indicate the CGRP (i) participates in regulation of the vascular adaptations that occur during normal pregnancy, (ii) has beneficial effects on the hypertension and increased mortality of experimental preeclampsia, and (iii) may exert differential effects on the systemic (i.e. maternal) and fetal components of utero-placental circulation. These findings may have important clinical implications.

Interaction between nitric oxide and prostaglandin E2 pathways in pregnant rat uteri

We examined the possible interrelationship between nitric oxide (NO) and cyclooxygenase (COX) products in the uterus during pregnancy and labor. Results indicate that 1) rat uteri during labor, at term, demonstrated a 69% decrease in nitrite production and a 217% increase in prostaglandin E2 (PGE2) production compared with day 18 of pregnancy; 2) interleukin-1 beta (IL-1 beta) induced a pronounced elevation of both nitrites and PGE2 in rat uteri; 3) diethylenetriamine/NO, a donor of NO, induced a significant increase of PGE2 production by the uterus in a dose-dependent manner; 4) NG-nitro-L-arginine methyl ester, an inhibitor of NO synthesis, markedly inhibited IL-1 beta-induced nitrite and PGE2 in rat uteri; this inhibitory action was reversed by coincubation with L-arginine; 5)exogenous PGE2 significantly inhibited IL-1 beta-induced, but not constitutive, nitrite production; and 6) inhibition of endogenous PGE2 by indomethacin substantially increased IL-1 beta-induced nitrite production. Thus the interaction between NO and COX pathways might be important in the regulation of uterine contractility during pregnancy and labor.

Involvement of a nitric oxide-cyclic guanosine monophosphate pathway in control of human uterine contractility during pregnancy

OBJECTIVES

The aims of the study were to investigate whether a nitric oxide-cyclic guanosine monophosphate relaxation pathway is present in the human uterus and whether it differentially inhibits contractility during pregnancy and labor.

STUDY DESIGN

Myometrial strips were obtained from pregnant women who were either in labor or not in labor and from nonpregnant women. Nitrites and cyclic guanosine monophosphate production by the tissues and contractile responses to nitric oxide modifiers were measured.

RESULTS

Biochemical assays revealed that nitric oxide (nitrites) and cyclic guanosine monophosphate are generated by the human uterus. Cyclic guanosine monophosphate production by the uterus was increased by L-arginine (the substrate for nitric oxide) and diethylamine/nitric oxide (a nitric oxide donor) and decreased by nitro-L-arginine methyl ester (an inhibitor of nitric oxide synthase). Spontaneous contractility in vitro was increased by nitro-L-arginine methyl ester and decreased by diethylamine/nitric oxide, which furthermore produced a dose-dependent inhibition of contractility, and the median effective dose of inhibition in tissues from nonlaboring pregnant patients (1.5 +/- 0.4 mumol/L) is substantially lower than in tissues from laboring pregnant (21.7 +/- 7.4 mumol/L or nonpregnant (20.8 +/- 4.4 mumol/L) women. These studies show that the nitric oxide-cyclic guanosine monophosphate system exists in the human uterus and that it inhibits contractility. Furthermore, the relaxation responsiveness to nitric oxide is elevated during pregnancy and decreased during labor.

CONCLUSION

A nitric oxide-cyclic guanosine monophosphate relaxation pathway is present in the human uterus and may be responsible for maintaining uterine quiescence during pregnancy. A decrease in uterine relaxation responsiveness to nitric oxide at term may play a role in the initiation of labor.

Effect of PGE in multiple experimental models. IX: In vivo effects of PGE on immune response of leucocytes to wounds

There have been conflicting results obtained when comparing the in vitro with in vivo effects of prostaglandin E (PGE) on immune function. The in vitro studies have demonstrated immune suppression with PGE administration while the in vivo studies demonstrated improved survival when utilizing infected models. To attempt to resolve this discrepancy, we evaluated the in vivo effect of PGE on host immune function utilizing multiple rat models. PGE was found to have no effect on the ability of leucocytes to infiltrate a sponge matrix wound over a 2-week period of study. PGE also failed to alter the percentage of T-lymphocyte subset populations infiltrating the sponge matrix model. There was noted to be no effect of PGE on the ability of neutrophils to chemiluminescence, or on metabolic function of lymphocytes. In conclusion, PGE does not appear to have immunosuppressive properties when studied using certain in vivo models.

Effect of blood transfusion on immune function. IX. Effect on lymphocyte metabolism

Blood transfusions have been repeatedly shown to be immunosuppressive in nature. The intracellular mechanisms of this immunosuppression have not been extensively investigated. We investigated the effect of blood transfusions on lymphocyte intracellular metabolism of glucose and amino acids, as well as levels of adenosine deaminase activity and nucleotide triphosphate concentrations. Blood transfusions were found to increase the rate of glucose and glutamine metabolism, to increase nucleotide triphosphate concentrations, and to increase the level of adenosine deaminase activity. This increased level of lymphocyte metabolism in the face of immunosuppression would appear to indicate that the transfusion-induced immunosuppression is an active dynamic process.

Effect of ibuprofen on the inflammatory response to surgical wounds

Patients suffering severe trauma frequently become immunosuppressed following injury. This can predispose patients to infectious sequelae. Biochemically, these patients synthesize excessive quantities of cyclooxygenase products (prostaglandins). It has been hypothesized that the prostaglandins cause the immunosuppression and that inhibition of the cyclooxygenase enzyme could thus prevent the immunosuppression. We investigated the effect of the cyclooxygenase inhibitor ibuprofen on the inflammatory response. Rats were subjected to a 30% total body surface area burn and were administered either ibuprofen for a period of 7 days or 14 days, or were administered the carrier for 14 days. The rats were then killed and multiple immunologic variables were measured. Ibuprofen was found to decrease neutrophil chemiluminescence, lymphocyte blastogenesis, and helper/inducer T-lymphocyte infiltration of a sponge matrix model. The same ibuprofen protocol decreased survival in a cecal ligation and puncture model. In conclusion, the cyclooxygenase enzyme system appears to produce metabolites essential for optimal survival following traumatic injury.

Impact of exogenous insulinlike growth factor 1 on hepatic energy metabolism in burn injury

BACKGROUND

Insulinlike growth factor 1 (IGF-1) has previously been demonstrated to improve the nutritional status of burned animals. The method by which it achieves this result has not yet been fully elucidated, but may be the result of alterations in hepatic metabolism.

OBJECTIVE

To determine if IGF-1 is able to correct the burn-induced impairments in hepatic metabolic function.

DESIGN

Seventy-two Sprague-Dawley rats were subjected to a sham burn (n = 24), or a 50% total body surface area scald burn (n = 48). Half the scald burn group received 3 micrograms/kg per day of IGF-1. The remainder received a placebo. The rats were sequentially assayed for multiple components of hepatic function.

RESULTS

Insulinlike growth factor 1 corrected the burn-induced decrease in hepatic adenosine triphosphate concentration and prevented the burn-induced increase in hepatic ketone body levels. Insulinlike growth factor 1 was also able to prevent the burn-induced decrease in the hepatic acetoacetate-beta-hydroxybutyrate ratio. Since this ratio is directly proportional to mitochondrial redox potential this indicates that IGF-1 is also able to prevent the burn-induced impairment in hepatic redox potential.

CONCLUSIONS

These data indicate that part of the previously demonstrated beneficial effect of IGF-1 in burn injury may be due to its ability to improve multiple components of hepatic metabolism.

Effect of insulin-like growth factor 1 on host response to tumor

Oncology patients suffer multiple detrimental metabolic alterations. Among these are catabolism of tumor free body mass to supply nutrients to feed the tumor. This results not only in enhanced tumor growth but also poor wound healing and immunosuppression of the tumor host. Efforts are therefore being directed at finding methods for improving the nutritional status of the tumor host without enhancing tumor growth. We investigated the ability of two hormones, insulin-like growth factor-1 (IGF-1) and insulin, to improve physiologic function in tumor-bearing animals. Tumor-bearing animals received a continuous infusion of IGF-1 (2.20 mg/kg/day), insulin (820 microns/kg/day) or placebo via an osmotic minipump for 7 days. All animals were pair fed to eliminate nutritional intake as a variable. The placebo group lost 31.37 +/- 4.3 g of tumor free body mass during the study period. The insulin treated group lost 26.34 +/- 7.42 g and the IGF-1 group lost 5.07 +/- 3.25 g (P < 0.001, ANOVA). IGF-1 treatment failed to alter plasma glucose, lactate, or total amino acid concentration and failed to alter hepatic ketone body concentrations, but did improve hepatic mitochondria redox potential. Finally, IGF-1 improved splenic weight by 110% and splenic lymphocyte count by 300%. In conclusion IGF-1 appears to offer potential in supporting tumor free host body mass without stimulating tumor growth.

Blockade of prostaglandin products augments macrophage and neutrophil tumor necrosis factor synthesis in burn injury

Cyclooxygenase products are believed to be a major regulator of host tumor necrosis factor-alpha (TNF-alpha) production in response to trauma and sepsis. To study this relationship, Lewis rats underwent a 30% burn or sham burn. Dimethyl-prostaglandin E (dPGE, 50 micrograms/kg), ibuprofen (IFU, 2 mg/kg), or saline was administered twice daily. Rats were sacrificed at Day 7 to obtain Kupffer cells, peritoneal macrophages, splenic macrophages, and neutrophils. For in vivo studies, 10(6) cells from each group were cultured with 10 micrograms of lipopolysaccharide (LPS). For in vitro studies, cells from the burn and sham groups were cultured with LPS and dPGE (10 micrograms/ml), IBU (10 micrograms/ml), or saline. The supernatants were harvested after 2, 6, and 24 hr of culture and assayed for TNF-alpha (mu/ml) by L929 cytolysis. Burn injury resulted in a significant increase in Kupffer cell and neutrophil TNF-alpha production compared to the sham group (P < 0.001, ANOVA). The administration of IBU to burned animals led to a pronounced elevation of TNF-alpha production by Kupffer cells, peritoneal macrophages, and neutrophils compared to vehicle-treated burned animals (P < 0.001, ANOVA). With in vitro studies, IBU increased Kupffer cell, peritoneal macrophage, and neutrophil TNF-alpha release by 213, 327, and 198%, respectively (P < 0.05, ANOVA). dPGE caused a marked decrease in Kupffer cell and peritoneal macrophage TNF-alpha synthesis by 50 and 43%, respectively (P < 0.01, ANOVA). In conclusion, prostaglandins are critical for down regulating TNF-alpha production. Clinical use of cyclooxygenase inhibitors may result in adverse outcomes due to the excessive TNF-alpha production.

Effect of thermal injury and sepsis on neutrophil function

Burn injury and sepsis have been repeatedly demonstrated to impair the function of circulating (blood) neutrophils. As a result of the difficulty in harvesting and purifying neutrophils from the burn wound, there have been minimal investigations to date on the effect of burn injury and sepsis on the function of neutrophils which have reached the wound. We utilized a sponge matrix model in order to obtain neutrophils from burned and burned-infected rats. Despite having a higher concentration of neutrophils in the blood, both the burned and burned-infected rats were noted to have a decreased number of neutrophils infiltrating the sponge compared with the controls (1.91 +/- 0.30 x 10(6), 2.31 +/- 0.47 x 10(6), and 4.82 +/- 0.64 x 10(6) neutrophils per sponge, respectively). Blood neutrophils from both the burned and burned-infected rats had a greater chemiluminescence capacity than neutrophils from the control group (p < 0.0001). This enhanced capacity was not present with sponge neutrophils obtained from the burned-infected group. The diminished capacity may have been the result of a decreased concentration of prostaglandin E in the sponge fluid of the burned-infected rats compared with that of the burned or control rats (52 +/- 9, 135 +/- 15, and 114 +/- 13 pg/mL of sponge fluid, respectively).

Evidence for Kupffer cell activation by burn injury and Pseudomonas exotoxin A

Postburn metabolic and immunological alterations may in part be due to translocation of gut exotoxin and endotoxin, which can result in tumour necrosis factor (TNF) and prostaglandin E (PGE) production by macrophages. We evaluated the effect of burn injury, plus exotoxin and endotoxin on TNF-alpha and PGE production by Kupffer cells, and peritoneal macrophages. Adult Wistar rats underwent 30 per cent TBSA burn or sham burn. Kupffer cells were harvested from rat livers and peritoneal macrophages from the abdominal cavity 24 h postburn. They were cultured overnight at 1 x 10(6) cells/ml and stimulated with saline, 5 micrograms/ml of Pseud. aeruginosa Exotoxin A (Exo-A), 5 micrograms/ml of Pseud. aeruginosa Endotoxin (Endo), Exo-A + Endo, or Exo-A + Endo + the PGE derivative 16,16 dimethyl-PGE (dPGE) (10 micrograms/ml). The supernatants were harvested after 4, 24 and 48 h of culture and assayed for TNF-alpha and PGE. Results showed that burn injury induced an increase in TNF-alpha and PGE production by Kupffer cells stimulated with Exo-A, Endo, and both Exo-A + Endo (P < 0.05). The release of TNF-alpha by Kupffer cells was downregulated by exogenous PGE (P < 0.05). The increased TNF-alpha production was inversely related to PGE levels. In conclusion, both burn injury and Exo-A potentiate the responsiveness of Kupffer cells and peritoneal macrophages to endotoxin as measured by the rate of production of TNF-alpha and PGE. PGE may locally downregulate the immune response by limiting Kupffer cells' and peritoneal macrophages' TNF-alpha production.

Alterations in intracellular lymphocyte metabolism induced by infection and injury

The effects of burn injury and sepsis on intracellular lymphocyte metabolism were evaluated using a rat model. Adult Lewis rats were subjected to a sham burn, a 30% full-thickness burn, or a 30% full-thickness burn which was infected with Pseudomonas aeruginosa. One week later the animals were sacrificed, and the splenic lymphocytes were harvested and cultured for 24 hr with mitogen stimulation. Lymphocytes from the burned-infected rats were found to utilize more glucose and certain amino acids than did lymphocytes obtained from the other two groups. Lymphocytes obtained from the burned-infected group had lower levels of the immunologically important enzyme, adenosine deaminase, than did the lymphocytes obtained from the other two groups. In summary, sepsis appears to alter a number of intracellular lymphocyte metabolic processes. These alterations may be found to be predictive of early sepsis.

Metabolic abnormalities of mitochondrial redox potential in postburn multiple system organ failure

Forty-five burn patients underwent sequential assays for plasma acetoacetate and beta-hydroxybutyrate concentrations as well as plasma amino acid levels. Those patients who went on to develop multiple system organ failure were noted to have a decrease in their acetoacetate concentration with time, whereas there was no change in those patients who failed to develop multiple system organ failure. The plasma concentration of beta-hydroxybutyrate was not altered by multiple system organ failure. In addition, the plasma acetoacetate/beta-hydroxybutyrate ratio was found to be directly related to the plasma concentration of branched chain amino acids and inversely related to the concentration of aromatic amino acids.

[Endothelial cell injury induced by linoleic acid hydroperoxide and atherosclerosis]

Effect of lipid peroxidation on the development of atherosclerotic lesions was studied in 10 diet-induced hyper cholesterolemic rabbits. By the end of the 3rd week of hypercholesterolemia, lipid peroxidative injury of the endothelial cells was induced by injecting linoleic acid hydroperoxide into a defined segment of the carotid artery. By the end of the 8th and 10th week light and electron microscopy revealed that atherosclerotic lesions mainly the fibrous plaques developed in certain segments of the artery described. The results indicate that under hypercholesterolemic condition, endothelial peroxidative injury may promote and intensify the process of atherogenesis. Furthermore, endothelial peroxidative injury which is characterised by the presence of plasma membrane blebbing can also be induced by hypercholesterolemia.