Increasing intracellular cAMP and cGMP inhibits cadmium-induced oxidative stress in rat submandibular saliva

Environmental particulate matter-one of the culprits in the development of caries

With the development of society, ecological and environmental problems have gradually become the focus of attention of countries around the world, among which environmental particulate matter poses a major harm to health. This article elucidates the association between environmental particulate matter and dental caries and provides new insights into the underlying mechanisms. In addition, this study emphasizes the role of oxidative stress in the occurrence and development of dental caries, and a new research pathway based on the interaction between oxidative stress and dental caries based on the Nrf2 pathway has become the focus of future research on the pathogenesis of dental caries. The relevant content of this review can provide a certain theoretical basis for the follow-up multidisciplinary joint research of researchers, and provide a certain reference for public health personnel and policymakers to formulate prevention strategies and public health interventions, carry out more accurate individualized treatment for high-risk groups, implement key prevention and treatment, and promote the overall improvement of effective prevention and treatment of caries. Ultimately, more attention must be paid to addressing the relationship between environmental particulate pollution and dental caries, with a focus on pollution control and reducing preventable environmental risks in order to protect oral health more broadly.

Correlation Between Urinary Heavy Metals and Early Childhood Caries in a Typical Industrial and Mining Area

In order to assess the association between urinary heavy metals and early childhood caries (ECC), a survey of deciduous tooth decay and urinary heavy metal concentrations of 408 children was conducted in a typical industrial and mining area. The results indicated that urinary heavy metal concentrations were ranked as Zn > Fe > Cu > Pb > Ni > Cd > As > Cr > Mn > Hg. The zero-inflated negative binomial model identified Hg as a significant risk factor for ECC (P25 ~ P75, OR = 3.499; > P75, OR = 3.184). Bayesian kernel machine regression further revealed that Pb, Cd, and Hg were positively correlated with ECC. Additional analysis using the Wilcoxon rank sum test and restricted cubic splines confirmed a positive correlation between the urinary concentrations of Pb, Cd, As, and Hg and the number of ECC (p < 0.05). Moreover, Bayesian kernel function regression and weighted quantile sum regression indicated that combined exposure to heavy metals was positively associated with ECC, with Hg (0.420) being the most dominant contributor, followed by As, Pb, and Cd. In conclusion, this study demonstrated a significant positive correlation between urinary heavy metals and both the occurrence and severity of ECC, with Hg identified as the most influential factor. It was recommended to minimize children's exposure to heavy metals to protect their dental health.

Impact of bone marrow mesenchymal stem cells on the submandibular gland structure of adult male albino rats exposed to cadmium chloride toxicity

OBJECTIVE

This study was carried out in submandibular salivary glands of rats to demonstrate the changes induced by cadmium intoxication and the possible prophylactic and therapeutic effects of bone marrow mesenchymal stem cells (BMSCs).

DESIGN

Sixty-five rats were divided into five groups. Rats in Group I were controls while those of Group II received daily dose of 10 mg/kg cadmium for 24 days. Rats in Group III received single prophylactic dose of 1 × 106 BMSCs one week before cadmium administration. Rats of Group IV were concomitantly administered cadmium and BMSCs, while those of Group V received cadmium for 24 days and were then treated with single dose of 1 × 106 BMSCs. Rats of Groups I, II, III, and IV were euthanized at the end of the experiment while those of Group V were euthanized one week later. Salivary gland specimens were processed and stained with H&E and inducible nitric oxide synthase; other specimens were used to demonstrate metallothionein gene expression using RT-PCR, malondialdehyde and catalase enzymes were detected by ELISA.

RESULTS

Groups III and IV had nearly comparable findings to Group I regarding histological pattern with normal gland features. Group III recorded a lower fold of change for metallothionein gene (1.14 ± 0.20), a lower malondialdehyde enzyme (21.67 ± 1.63 nmol/mg), and a higher catalase enzyme (66.33 ± 2.16 mmol/mg). Regarding all variables, significant differences were found between the different groups (P < 0.001).

CONCLUSION

BMSCs have prophylactic and therapeutic effects against cadmium-induced cytotoxicity in rat salivary glands.

Brain metastases: It takes two factors for a primary cancer to metastasize to brain

Brain metastasis of a cancer is a malignant disease with high mortality, but the cause and the molecular mechanism remain largely unknown. Using the samples of primary tumors of 22 cancer types in the TCGA database, we have performed a computational study of their transcriptomic data to investigate the drivers of brain metastases at the basic physics and chemistry level. Our main discoveries are: (i) the physical characteristics, namely electric charge, molecular weight, and the hydrophobicity of the extracellular structures of the expressed transmembrane proteins largely affect a primary cancer cell’s ability to cross the blood-brain barrier; and (ii) brain metastasis may require specific functions provided by the activated enzymes in the metastasizing primary cancer cells for survival in the brain micro-environment. Both predictions are supported by published experimental studies. Based on these findings, we have built a classifier to predict if a given primary cancer may have brain metastasis, achieving the accuracy level at AUC = 0.92 on large test sets.

Therapeutics studies and biological properties of Teucrium polium (Lamiaceae)

Teucrium polium has been used in traditional medicine as antifungal, antipyretic, antispasmodic, and antibacterial. It is consumed by many jordanians for the treatment of many diseases. The effects of this plant have been investigated in kidney, liver, and brain. Its antidiabetic, antimicrobial, antioxidant, and anticancer effects have been introduced. Polyphenolic compound, flavonoids, monoterpenes, alkanoides, and essential oils were identified. Several studies revealed that this plant has a hypoglycemic effect and can help to control blood sugar. It was reported that plants containing flavonoids and phenolics compounds exhibit a large array of biological activities like genotoxicity (chromosomal aberrations and sister chromatid exchange) and oxidative stress damage. These phytochemicals are found in herbal and vegetables plants, as well as being reliably protective against oxidative stress damage and lipid peroxidation. In addition, T. polium has secondary effects on different organs, namely liver, kidney and at high doses this plant becomes toxic. In conclusion, this review investigates many pharmacologicals properties and side effects of T. polium.

Environmental Cadmium Exposure and Dental Indices in Orthodontic Patients

BACKGROUND

Previous studies have shown that environmental cadmium exposure could disrupt salivary gland function and is associated with dental caries and reduced bone density. Therefore, this cross-sectional study attempted to determine whether tooth decay with tooth loss following cadmium exposure is associated with some dental or skeletal traits such as malocclusions, sagittal skeletal pattern, and tooth decay.

METHODS

Between August 2019 and June 2020, 60 orthodontic patients with no history of previous orthodontics, functional appliances, or surgical treatment were examined. The patients were stratified into two groups according to their urine cadmium concentrations: high (>1.06 µg/g creatinine, n = 28) or low (<1.06 µg/g creatinine, n = 32).

RESULTS

The patients were 25.07 ± 4.33 years old, and most were female (female/male: 51/9 or 85%). The skeletal relationship was mainly Class I (48.3%), followed by Class II (35.0%) and Class III (16.7%). Class I molar relationships were found in 46.7% of these patients, Class II molar relationships were found in 15%, and Class III molar relationships were found in 38.3%. The mean decayed, missing, and filled surface (DMFS) score was 8.05 ± 5.54, including 2.03 ± 3.11 for the decayed index, 0.58 ± 1.17 for the missing index, and 5.52 ± 3.92 for the filled index. The mean index of complexity outcome and need (ICON) score was 53.35 ± 9.01. The facial patterns of these patients were within the average low margin (26.65 ± 5.53 for Frankfort-mandibular plane angle (FMA)). There were no significant differences in the above-mentioned dental indices between patients with high urine cadmium concentrations and those with low urine cadmium concentrations. Patients were further stratified into low (<27, n = 34), average (27-34, n = 23), and high (>34, n = 3) FMA groups. There were no statistically significant differences in the urine cadmium concentration among the three groups. Nevertheless, a marginally significant p-value of 0.05 for urine cadmium concentration was noted between patients with low FMA and patients with high FMA.

CONCLUSION

This analysis found no association between environmental cadmium exposure and dental indices in our orthodontic patients.

Beneficial Impact of an Extract from the Berries of Aronia melanocarpa L. on the Oxidative-Reductive Status of the Submandibular Gland of Rats Exposed to Cadmium

Oxidative stress underlies the pathomechanisms of toxic action of cadmium (Cd), including its damaging impact on the oral cavity. This study investigated whether the administration of an extract from Aronia melanocarpa L. berries (AME), characterized by their strong antioxidative potential, may have a beneficial impact on the oxidative-reductive status of the submandibular gland in an experimental model of low-level and moderate human environmental exposure to cadmium. The main markers of the antioxidative status (glutathione reductase, superoxide dismutase, catalase, reduced glutathione, total antioxidative status (TAS)), total oxidative status (TOS), oxidative stress index (OSI = TOS/TAS), and lipid peroxides, as well as cadmium concentration, were evaluated in the submandibular gland tissue of female Wistar rats who received a 0.1% aqueous AME and/or a diet containing 0, 1, and 5 mg Cd/kg for 3 and 10 months. The treatment with cadmium decreased the activities of antioxidative enzymes (29%-74%), reduced glutathione concentration (45%-52%), and TAS and increased TOS, resulting in the development of oxidative stress and enhanced concentration of lipid peroxides in the submandibular gland. The administration of AME at both levels of exposure to cadmium offered significant protection against these actions of this xenobiotic. After the 10 month exposure to the 1 and 5 mg Cd/kg diet, TAS was decreased by 77% and 83%, respectively, TOS, OSI, and lipid peroxides concentration were increased by 50% and 52%, respectively, 11.8-fold and 14.4-fold, respectively, and 2.3-fold and 4.3-fold, respectively, whereas, in the case of the extract co-administration, the values of these parameters did not differ compared to the control group. The results indicate that the consumption of aronia products under exposure to cadmium may have a beneficial impact on the oxidative-reductive status of the submandibular gland and prevent oxidative stress development and enhanced lipid peroxidation in this salivary gland.

Alterations of the Brain Proteome and Gut Microbiota in d-Galactose-Induced Brain-Aging Mice with Krill Oil Supplementation

Brain aging is commonly associated with neurodegenerative disorders, but the ameliorative effect of krill oil and the underlying mechanism remain unclear. In this study, the components of krill oil were measured, and the antiaging effects of krill oil were investigated in mice with d-galactose (d-gal)-induced brain aging via proteomics and gut microbiota analysis. Krill oil treatment decreased the expression of truncated dopamine- and cAMP-regulated phosphoproteins and proteins involved in the calcium signaling pathway. In addition, the concentrations of dopamine were increased in the serum (p < 0.05) and brain (p > 0.05) due to the enhanced expressions of tyrosine-3-monooxygenase and aromatic l-amino acid decarboxylase. Moreover, krill oil alleviated gut microbiota dysbiosis, decreased the abundance of bacteria that consume the precursor tyrosine, and increased the abundance of Lactobacillus spp. and short-chain fatty acid producers. This study revealed the beneficial effect of krill oil against d-gal-induced brain aging and clarified the underlying mechanism through proteomics and gut microbiota analysis.

Effect of phosphodiesterase inhibitors on renal functions and oxidant/antioxidant parameters in streptozocin-induced diabetic rats

The goal of this study was to investigate the effect of different phosphodiesterase inhibitors (PDEIs), on renal oxidant/antioxidant balance in diabetic rats. Our study was conducted on 125 rats, diabetes was induced in 100 rats by a single administration of streptozocin (STZ). Diabetic rats were divided into four equal groups. The first group was assigned as diabetic control, the remaining three groups were treated with pentoxifylline, sildenafil and milrinone via drinking water for 15 successive days, another group of 25 normal rats was assigned as non-diabetic control. Significant increase in plasma levels of glucose, urea, creatinine, malondialdehyde (MDA), and nitric oxide (NO) with a concomitant decrease in the levels of insulin, reduced glutathione (GSH), glutathione peroxidase (Gpx), superoxide dismutase (SOD), catalase (CAT), and total antioxidant capacity (TAC) were observed in diabetic rats. These alterations were reverted back to near normal level after treatment with PDEIs. Our data seem to suggest a potential role of PDEIs in maintaining health in diabetes by reducing the progression of diabetic nephropathy.

Protective Effect of Increased Zinc Supply against Oxidative Damage of Sublingual Gland in Chronic Exposure to Cadmium: Experimental Study on Rats

Cadmium is one of the main chemical pollutants found in the daily environment of developed countries. Cigarettes are a significant source of that metal, which makes it important in terms of oral cavity health. The aim of this study was to determine if increased supply of zinc in chronic exposure to cadmium might protect the sublingual gland structure against oxidative damage. The experiment took 12 months and was conducted on 72 adult male rats. They were randomized into 9 groups. Eight groups received cadmium in drinking water (as CdCl₂) at 5 or 50 mg Cd/dm³ and/or zinc (as ZnCl₂) at 30 or 60 mg Zn/dm³. The control group received regular water. In the sublingual gland of all animal groups, levels of oxidative parameters were measured. The oxidative stress index was calculated as a TOS/TAS ratio. Cadmium exposure at 5 mg and 50 mg Cd/dm³ induced oxidative stress in the sublingual glands of the rats. Cadmium reduced the TAS and GSH levels and increased LPO, H₂O₂, TOS, and OSI. In cadmium exposure conditions, increasing the supply of zinc by 79% or 151%, as compared to the standard dietary intake of this microelement, completely prevented the reduction of TAS and GSH levels and accumulation of LPO, H₂O₂, and TOS in the examined gland at both exposure levels to that metal. The outcome data confirm the protective effect of increased zinc intake on the sublingual gland tissue in chronic cadmium exposure.

Potential contribution of insecticide exposure and development of obesity and type 2 diabetes

The introduction of insecticides has greatly improved agricultural productivity and human nutrition; however, the wide use of insecticides has also sparked growing concern over their health impacts. Increased rate of cancers, neurodegenerative disorders, reproductive dysfunction, birth defects, respiratory diseases, cardiovascular diseases and aging have been linked with insecticide exposure. Meanwhile, a growing body of evidence is suggesting that exposure to insecticides can also potentiate the risk of obesity and type 2 diabetes. This review summarizes the relationship between insecticide exposure and development of obesity and type 2 diabetes using epidemiological and rodent animal studies, including potential mechanisms. The evidence as a whole suggests that exposure to insecticides is linked to increased risk of obesity and type 2 diabetes.

Reduction of chlorpyrifos-induced toxicity in human lymphocytes by selected phosphodiesterase inhibitors

One of the most famous and commonly used compounds from organophosphate (OP) family is chlorpyrifos (CP) which is widespreadly used as a powerful insecticide. Previous studies have shown that OPs induce oxidative stress, inflammation and apoptosis by generating the free radicals. The protective effects of three members of phosphodiesterase inhibitor (PDEI) family, including rolipram (RLP), milrinon (MLR) and pentoxifylline (PTX) were evaluated in the human lymphocytes against CP's toxicity. In this case, the level of oxidative stress biomarkers, the viability of the cells and the rate of apoptosis by flow cytometry were investigated. The results of this study revealed that CP makes a significant increase in the level of inflammatory and oxidative stress markers such as meyloperoxidase (MPO), lipid peroxidation (LPO), total thiol molecules (TTM) and total antioxidant potential (TAP), and also makes an enhancement in the rate of apoptosis process. On the other hand, PDEIs and specifically the combination of them restored the negative effects of CP and significantly prevented the apoptosis and oxidative stress imbalance. It is concluded that these PDEIs have positive effects in attenuation, recovery, and protection of CP-induced toxicity in the human lymphocytes.

A Review of the Benefits of Satureja Species on Metabolic Syndrome and Their Possible Mechanisms of Action

Metabolic syndrome, also known as insulin resistance disorder, is the simultaneous manifestation of multiple metabolic disorders in an individual. The present-day complementary and alternative therapies suggest several medicinal herbs that may have the potential to improve one or multiple complications of metabolic syndrome. All of them have their own limitations in efficacy and unwanted effects. Therefore, we reviewed species of Satureja as widespread medicinal herbs and potentially good remedies for metabolic syndrome. We reviewed literature found in PubMed and the ISI Web of Knowledge with the key word Satureja in the title. The influence of any species of Satureja on any disease or syndrome, enzymatic, metabolic, or physiological pathways, in human, animals, or in vitro conditions related to any characteristics of metabolic syndrome were considered. The main outcomes of treatment with Satureja species were categorized, and the possible mechanisms of action are discussed in this article.

cAMP attenuates the enhanced expression of Gi proteins and hyperproliferation of vascular smooth muscle cells from SHR: role of ROS and ROS-mediated signaling

We previously showed that angiotensin II (ANG II)-induced overexpression of inhibitory G proteins (Gi) was attenuated by dibutyryl-cAMP (db-cAMP) in A10 vascular smooth muscle cells (VSMC). Since enhanced levels of endogenous ANG II contributed to the overexpression of Gi protein and hyperproliferation of VSMC from spontaneously hypertensive rats (SHR), the present study was therefore undertaken to examine if cAMP could also attenuate the overexpression of Gi proteins and hyperproliferation of VSMC from SHR and to explore the underlying molecular mechanisms responsible for this response. The enhanced expression of Giα proteins in VSMC from SHR and Nω-nitro-L-arginine methyl ester hypertensive rats was decreased by db-cAMP. In addition, enhanced inhibition of adenylyl cyclase by inhibitory hormones and forskolin-stimulated adenylyl cyclase activity by low concentration of GTPγS in VSMC from SHR was also restored to Wistar-Kyoto (WKY) levels by db-cAMP. Furthermore, db-cAMP also attenuated the hyperproliferation and the increased production of superoxide anion, NAD(P)H oxidase activity, overexpression of Nox1/Nox2/Nox4 and p47phox proteins, increased phosphorylation of PDGF-receptor (R), EGF-R, c-Src, and ERK1/2 to control levels. In addition, the protein kinase A (PKA) inhibitor reversed the effects of db-cAMP on the expression of Nox4 and Giα proteins and hyperproliferation of VSMC from SHR to WKY levels, while stimulation of the exchange protein directly activated by cAMP did not have any effect on these parameters. These results suggest that cAMP via PKA pathway attenuates the overexpression of Gi proteins and hyperproliferation of VSMC from SHR through the inhibition of ROS and ROS-mediated transactivation of EGF-R/PDGF-R and MAPK signaling pathways.

Evaluation of the protective effect of Beta glucan on amikacin ototoxicity using distortion product otoacoustic emission measurements in rats

Objectives

This experimental study investigated the possible protective effect of beta glucans on amikacin ototoxicity.

Methods

Thirty-eight rats with normal distortion product otoacoustic emissions (DPOAEs) were divided into four groups. Group K was the control group. Group A was injected intramuscularly (i.m.) with amikacin 600 mg/kg/day between days 1-15. Group AB was given beta glucan gavage 1 mg/kg/day on days 0-15 and given amikacin 600 mg/kg/day i.m. on days 1-15. Group B was administered only beta glucan gavage, 1 mg/kg/day, on days 0-15. The DPOAEs were elicited in different frequency regions between 2,003 and 9,515 Hz, as distortion product diagrams (DPgrams), before and after the medication was administered, in all groups, on days 1, 5, 10, and 15.

Results

No significant changes in the DPgrams were observed in group K. In group A, significant deterioration was observed at the 8,003 and 9,515 Hz frequencies on day 10, and at the 3,991, 4,557, 5,660, 6,726, 8,003, and 9,515 Hz frequencies on day 15. For group AB, statistically significant deterioration was observed at the 2,824, 8,003, and 9,515 Hz frequencies on day 15. The results for group B showed a significant improvement of hearing at the 2,378, 2,824, 3,363, and 3,991 Hz frequencies on day 1, at the 3,363, 3,991, and 8,003 Hz frequencies on day 10, and at the 8,003 Hz frequency on day 15.

Conclusion

This study suggests that amikacin-induced hearing loss in rats may be limited to some extent by concomitant use of beta glucan.

Adult tooth loss for residents of US coal mining and Appalachian counties

OBJECTIVES

The authors compared rates of tooth loss between adult residents of Appalachian coal-mining areas and other areas of the nation before and after control for covariate risks.

METHODS

The authors conducted a cross-sectional secondary data analysis that merged 2006 national Behavioral Risk Factor Surveillance System data (BRFSS) (N = 242 184) with county coal-mining data and other county characteristics. The hypothesis tested was that adult tooth loss would be greater in Appalachian mining areas after control for other risks. Primary independent variables included main effects for coal-mining present (yes/no) residence in Appalachia (yes/no), and their interaction. Data were weighted using the BRFSS final weights and analyzed using SUDAAN Proc Multilog to account for the multilevel complex sampling structure. The odds of two measures of tooth loss were examined controlling for age, race\ethnicity, drinking, smoking, income, education, supply of dentists, receipt of dental care, fluoridation rate, and other variables.

RESULTS

After covariate adjustment, the interaction variable for the residents of Appalachian coal-mining counties showed a significantly elevated odds for any tooth loss [odds ratio (OR) = 1.19, 95% CI = 1.02, 1.38], and greater tooth loss measured by a 4-level edentulism scale (OR = 1.20, 95% CI = 1.05, 1.36). The main effect for Appalachia was also significant for both measures, but the main effect for coal mining was not.

CONCLUSIONS

Greater risk of tooth loss among adult residents of Appalachian coal-mining areas is present and is not explained by differences in reported receipt of dental care, fluoridation rates, supply of dentists or other behavioral or socioeconomic risks. Possible contributing factors include mining-specific disparities related to access, behavior or environmental exposures.

Beneficial effect of phosphodiesterase-5 inhibitor in experimental inflammatory bowel disease; molecular evidence for involvement of oxidative stress

ABSTRACT Inflammatory bowel disease (IBD) is a common and chronic gastrointestinal disorder characterized by intestinal inflammation and mucosal tissue damage. Reactive oxygen metabolites (ROMs) play a pathogenic role in IBD. We aimed to examine the protective effect of sildenafil, a cGMP phosphodiesterase inhibitor, in the experimental mouse model of IBD. Intrarectal instillation of acetic acid was used to induce IBD. Prednisolone was used as the standard drug for comparison. Sildenafil was used at doses of 0.75, 1.5, and 3 mg/kg. Biochemicals and macroscopic and microscopic examinations of colonic tissue were performed. Results indicated that activity of myeloperoxidase (MPO) and lipid peroxidation product (TBARS) markers of oxidative stress are increased in acetic acid-treated groups and are recovered by sildenafil pretreatment and prednisolone. Sildenafil- (1.5 and 3 mg/kg) and prednisolone-treated groups showed significantly lower score values of macroscopic and microscopic characters when compared to the acetic acid-treated group. The beneficial effect of sildenafil (3 mg/kg) was comparable to that of prednisolone. It is concluded that sildenafil is helpful in the management of IBD, which is presumably related to its strong antioxidative stress potential mediated through enhanced cGMP. Results of proper clinical trials will determine the possible efficacy of phosphodiesterase-5 inhibitors in human IBD.

Biochemical and histopathological evidences for beneficial effects of satureja khuzestanica jamzad essential oil on the mouse model of inflammatory bowel diseases

The essential oil from Satureja Khuzestanica Jamzad (SKEO), an endemic plant from Iran, was evaluated for its activity against inflammatory bowel disease (IBD). SKEO was examined on the experimental mouse model of inflammatory bowel disease, which is acetic acid-induced colitis. Prednisolone was used as the standard drug for comparison. Biochemical, macroscopic, and microscopic examinations of colon were performed. Lipid peroxidation significantly increased in acetic acid-treated mice in comparison to the normal group (4.88 vs. 3.02 mumol/g) and was significantly restored by SKEO (500, 1000, 1500 ppm) and prednisolone treatment. The mean percentage of decreases of lipid peroxidation in SKEO (500, 1000, 1500 ppm)- and prednisolone-treated groups were 10.5, 28.5, 42.85, and 33.33 of control, respectively. The myeloperoxidase activity significantly increased in acetic acid-treated mice in comparison to the normal group (4.1 vs. 0.8 U/g) and significantly restored in SKEO (1000 and 1500 ppm)- and prednisolone-treated groups. The mean percentage of decreases of myeloperoxidase activity in SKEO (1000 and 1500 ppm)- and prednisolone-treated groups were 24.56, 50, and 52.63 of control, respectively. SKEO (1000 and 1500 ppm)- and prednisolone-treated groups showed significantly lower score values of macroscopic and microscopic characters when compared to the acetic acid-treated group. The beneficial effect of SKEO (1500 ppm) was comparable to that of prednisolone. Known antioxidant, antimicrobial, antiinflammatory, and antispasmodic potentials of Satureja Khuzestanica may be the mechanisms by which this plant protects animals against experimentally induced IBD. Proper clinical investigation should be carried out to confirm the activity in human disease.

Relationship of oxidative stress in hepatitis B infection activity with HBV DNA and fibrosis

BACKGROUND

The aim of this study was to evaluate oxidative stress in various clinical forms of hepatitis B infection and to investigate its role in the development of the chronic form of the disease.

METHODS

Ninety-three patients with inactive hepatitis B surface antigen (HbsAg) carrier state (IHBCS), 65 patients with chronic hepatitis B infection (CHB), and 42 healthy adults were included in the study. The following values were measured and compared in patient groups: total antioxidant status (TAS), total oxidative stress (TOS), oxidative stress index (OSI), sulfhydryl (SH), lipid peroxidation (LOOH), catalase (CAT), and ceruloplasmin. In patients with chronic hepatitis B, these values were compared with HBV DNA and fibrosis levels.

RESULTS

ALT, TOS, LOOH, and OSI levels were higher in the CHB group compared to the other groups (P<0.001). Catalase levels increased in the CHB and IHBCS groups compared to the control group (P<0.001). Total aminooxidant and ceruloplasmin levels were found to be lowest in the CHB group and highest in the control group (P<0.001). Sulfhyrdyl was higher in the control group compared to the other groups (P<0.001). In the CHB group, there was no correlation between the HBV DNA and OSI (P>0.05).

CONCLUSIONS

These finding suggested that oxidative stress is associated with hepatitis B activity.

Biochemical evidence on the potential role of organophosphates in hepatic glucose metabolism toward insulin resistance through inflammatory signaling and free radical pathways

Several studies show that organophosphate pesticides exert several effects on glucose homeostasis. The current study investigates the influence of subchronic exposure to malathion (MT) on hepatic gluconeogenesis in relation to acetyl cholinesterase (AChE) inhibition, oxidative stress and inflammatory response in the rat. MT was administered by gavage at doses of 25, 50 and 100 mg/kg for 32 days. Fasting hyperglycemia was seen in line with an increased activity of hepatic phosphoenolpyruvate carboxykinase, glucose 6-phosphatase and tumor necrosis factor α. In addition to the impaired glucose tolerance and inhibition of AChE in a dose-dependent manner, there were significant increases in hepatic lipid peroxidation, carbonyl groups and 8-deoxyguanosine as the biomarkers of reactive oxygen species–mediated damage to lipid, protein and DNA, respectively. Altered quality of the liver in glucose production especially gluconeogenesis could be a compensatory mechanism against MT toxicity or even result in tissue damage. MT-induced insulin resistance in the liver occurs through oxidative and inflammatory signaling pathways.

Cadmium intoxication of pregnant rats and fetuses: interactions of copper supplementation

BACKGROUND AND AIMS

Cadmium (Cd) is an industrial and environmental pollutant that was shown to be involved in the development of some diseases. Due to high amounts of Cd in cigarettes, smokers and passive smokers are exposed to high amount of Cd. We aimed to determine whether Copper (Cu) supplementation would have a protective effect against Cd intoxication in pregnant rats and their fetuses.

METHODS

Experiments were performed on 27 adult female Wistar albino rats divided into three experimental groups. CdCl(2), CdCl(2) plus CuSO(4) and only drinking water was given to different groups for 21 days. We measured cadmium (Cd), malondialdehyde (MDA), reduced glutathione (GSH), myeloperoxidase (MPO), superoxide dismutase (SOD) and catalase (CAT) levels in dams' liver, dams' kidney, fetus liver, fetus kidney, and placenta of rats.

RESULTS

In all tissues of Cd and Cd + Cu-treated groups, Cd levels were found to be increased significantly when compared to control group. MDA levels and MPO activities were significantly increased whereas GSH levels, activities of SOD and CAT were decreased in Cd groups when compared to control group. Cu supplementation significantly prevented the increment in MDA levels and brought MPO activities back to control levels or below. Cd-induced reductions in GSH levels and SOD activities were also prevented by Cu supplementation. An increase of CAT activity after Cu supplementation was enough to revert to the control levels in some tissues.

CONCLUSIONS

Our findings suggest that Cu supplementation may have a protective effect against the Cd-induced oxidative stress in liver, kidney and placental tissues of pregnant rats and fetuses.

On the benefit of Teucrium in murine colitis through improvement of toxic inflammatory mediators

Regarding the role of free radicals in pathogenesis of inflammatory bowel disease (IBD), we were interested to investigate the effects of Teucrium persicum with approved antioxidant and anti-inflammatory properties in an experimental model of colitis. Immunologic colitis was induced by rectal administration of a mixture of 2,4,6-trinitrobenzene sulphonic acid (TNBS) and ethanol through rubber cannula into rats. Three different doses of Teucrium (100, 200, and 400 mg/kg) were gavaged in a duration of 10 days to rats. Endpoint markers of colitis included macroscopic and microscopic examination of colon tissue and measuring colonic cells concentrations of tumor necrosis factor-alpha (TNF-alpha), interlukin-1beta (IL-1beta), total antioxidant power as ferric reducing antioxidant power (FRAP), myeloperoxidase (MPO), and lipid peroxidation as thiobarbitoric acid-reactive substance (TBARS). Teucrium at all doses improved both macroscopic and histological damages of rats with colitis. Teucrium reduced colonic MPO activity and concentrations of cellular lipid peroxides, TNF-alpha, and IL-1beta, with a concomitant increase in FRAP value in rats with colitis. It is concluded that beneficial effects of Teucrium in experimental colitis is mediated through its antioxidant and anti-inflammatory potentials. Examination of this herbal medicine in patients with IBD as a supplement would further reveal the potential of Teucrium.

A review of the herbal phosphodiesterase inhibitors; future perspective of new drugs

Phosphodiesterase inhibitors (PDEIs) are a class of drugs that are widely used because of their various pharmacological properties including cardiotonic, vasodilator, smooth muscle relaxant, antidepressant, antithrombotic, bronchodilator, antiinflammatory and enhancer of cognitive function. In the recent years, interest in drugs of plant origin has been progressively increased. Some pharmacologically active substances that come from plants demonstrate PDEI activity. They mainly belong to alkaloids, flavonoids, and saponins. In this review, studies on herbal PDEI were reviewed and their possible therapeutic applications were discussed. Screening plants for PDE inhibitory activity may help to develop standardized phytotherapeutic products or find new sources for new lead structures with PDEI pharmacological activity. The studies discussed in this paper are mainly in vitro and for more reasonable and conclusive results, it is required to conduct in vivo and finally human and clinical tests.

Inhibition of tumor necrosis factor and nitrosative/oxidative stresses by Ziziphora clinopoides (Kahlioti); a molecular mechanism of protection against dextran sodium sulfate-induced colitis in mice

Inflammatory bowel disease (IBD) is a chronic condition of the intestine with unknown etiology involving multiple immune genetic and environmental factors. The authors were interested in examining the protective effect of Ziziphora clinopoides methanolic extract, an Iranian folk herbal medicine, on inflammatory mediators in experimental colitis. Colitis in NMRI mice was induced by oral administration of dextran sodium sulfate (DSS, 3%). Z. clinopoides was administrated orally at doses of 75, 150, and 300 mg/kg/day for 7 days. The level of lipid peroxidation (LP), total antioxidant capacity (TAC), total thiol molecules (TTM), antioxidant enzymes including superoxide dismutase (SOD) and catalase (CAT), and nitric oxide (NO) as a marker of nitrosative stress, and tumor necrosis factor alpha (TNF-alpha) as a mediator of inflammation and apoptosis were measured in the colon homogenate. Treatment by DSS increased bowel LP, NO, and TNF-alpha while decreasing TAC, SOD, CAT, and TTM. All measured parameters were improved by Z. clinopoides treatment and reached close to normal levels. The present study further supports the role of oxidative/nitrosative stresses and TNF-alpha in the pathogenesis of colitis and protective effects of this herb. The data are promising for further preclinical studies directed towards understanding mechanism of action and cross-species and cross-model comparisons for potential protective effects.

Improvement of inflammatory and toxic stress biomarkers by silymarin in a murine model of type one diabetes mellitus

Type 1 diabetes mellitus (T1DM) is characterized by an impairment of the insulin-secreting beta cells with an immunologic base. Inflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β, and free radicals are believed to play key roles in destruction of pancreatic β cells. The present study was designed to investigate the effect of Silybum marianum seed extract (silymarin), a combination of several flavonolignans with immunomodulatory, anti-oxidant, and anti-inflammatory potential on streptozotocin (STZ)-induced T1DM in mouse. Experimental T1DM was induced in male albino mice by IV injection of multiplelow- doses of STZ for 5 days. Seventy-two male mice in separate groups received various doses of silymarin (20, 40, and 80 mg/kg) concomitant or after induction of diabetes for 21 days. Blood glucose and pancreatic biomarkers of inflammation and toxic stress (IL-1β, TNF-α, myeloperoxidase, lipid peroxidation, protein oxidation, thiol molecules, and total antioxidant capacity) were determined. Silymarin treatment reduced levels of inflammatory cytokines such as TNF-α and IL-1β and oxidative stress mediators like myeloperoxidase activity, lipid peroxidation, carbonyl and thiol content of pancreatic tissue in an almost dose dependent manner. No marked difference between the prevention of T1DM and the reversion of this disease by silymarin was found. Use of silymarin seems to be helpful in T1DM when used as pretreatment or treatment. Benefit of silymarin in human T1DM remains to be elucidated by clinical trials.

Benefit of Satureja khuzestanica in subchronically rat model of cyclophosphamide-induced hemorrhagic cystitis

Cyclophosphamide (CP) as a widely used antineoplastic drug causes hemorrhagic cystitis (HC) mainly via induction of oxidative stress. Regarding established antioxidant potential of Satureja khuzestanica (Lamiaceae) essential oil (SKEO), we aimed to investigate its protective effects in a subchronic rat model of CP-induced HC. CP (6mg/kg/day) and SKEO (225mg/kg/day) were administered alone or in combination by gavage for 28 days. Histopathological changes were investigated by light microscopy. Plasma samples were assayed for lipid peroxidation and total antioxidant power as biomarkers of toxic stress. In the CP-treated animals, irregular mucus layer, severe hemorrhage and edema, infiltration of inflammatory cells, and accumulation of mast cells were observed. In the CP+SKEO group, a relatively normal urothelial topography with decreased number of mucosal mast cells and inflammatory cells were observed. Increased lipid peroxidation along with decreased total antioxidant capacity resulting from CP treatment was significantly recovered by SKEO co-treatment. It is concluded that SKEO protects rats from CP-induced HC by reduction of free radical-induced toxic stress. It is strongly recommended to examine SKEO in the clinic to approve its benefit in patients undertaking CP.

Association of environmental cadmium exposure with pediatric dental caries

BACKGROUND

Although animal experiments have shown that cadmium exposure results in severe dental caries, limited epidemiologic data are available on this issue.

OBJECTIVES

We aimed to examine the relationship between environmental cadmium exposure and dental caries in children 6-12 years of age.

METHODS

We analyzed cross-sectional data, including urine cadmium concentrations and counts of decayed or filled tooth surfaces, from the Third National Health and Nutrition Examination Survey. We used logistic and zero-inflated negative binomial (ZINB) regression to estimate the association between urine cadmium concentrations and caries experience, adjusting these analyses for potential confounders including environmental tobacco smoke (ETS).

RESULTS

Urine cadmium concentrations ranged from 0.01 to 3.38 ng/mL. Approximately 56% of children had experienced caries in their deciduous teeth, and almost 30% had been affected by caries in their permanent dentition. An interquartile range (IQR) increase in creatinine-corrected cadmium concentrations (0.21 microg/g creatinine) corresponded to a 16% increase in the odds of having experienced caries in deciduous teeth [prevalence odds ratio (OR)=1.16; 95% confidence interval (CI), 0.96-1.40]. This association was statistically significant in children with low ETS exposure (prevalence OR=1.30; 95% CI, 1.01-1.67). The results from the ZINB regression indicated that, among children with any caries history in their deciduous teeth, an IQR increase in cadmium was associated with 17% increase in the number of decayed or filled surfaces. We observed no association between cadmium and caries experience in permanent teeth.

CONCLUSIONS

Environmental cadmium exposure may be associated with increased risk of dental caries in deciduous teeth of children.

The effects of increased cAMP content on inflammation, oxidative stress and PDE4 transcripts during Brucella melitensis infection

Cyclic AMP (cAMP) is a key intracellular second messenger which at increased levels has been shown to have anti-inflammatory and tissue-protective effects. Its concentration is determined by the activities of both adenylate cyclase (AC) and the phosphodiesterase (PDE) enzymes. The aim of this study was to compare the effects of increased cAMP and glucocorticoid dexamethasone administration on B. melitensis-induced lipid peroxidation, Brucella suppressed antioxidant enzyme activities and PDE4 transcripts in rats. Intracellular cyclic AMP level was elevated by two different approaches; activation of AC and inhibition of PDE activities. Rats were inoculated with B. melitensis for seven days then a single dose of nonselective PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX), the adenylate cyclase activator forskolin and dexamethasone were administrated to each infected group, and animals were challenged for 48 h. Brucella-induced lipid peroxidation was significantly reduced by the cAMP elevating agents as well as dexamethasone administration in plasma, liver and spleen. The antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were significantly decreased by the pathogen. Whilst suppressed GSH-Px activity was reversed by cAMP elevating agents, SOD activity was not restored. Superoxide generating enzyme xanthine oxidase activity was not altered at the end of the infection period. Brucella infection increased plasma IL-12 level and this effect was also suppressed by the cAMP elevating agents, whereas TNF-alpha, IFN-gamma and IL-10 levels were unchanged. Intracellular cAMP levels are entirely hydrolyzed by cAMP-specific PDE 4 isozymes (PDE4s) in inflammatory and immunocompetent cells. Brucella reduced mRNA transcript levels for PDE4A by 40%, though PDE4B and 4D transcriptions were being unaffected in spleen. It was concluded that B. melitensis infection decreased activity of the antioxidant defence system, induced lipid peroxidation and suppressed PDE4A transcription. Administration of cAMP elevating agents exhibited similar affect with dexamethasone on lipid peroxidation, IL-12 production and antioxidant enzyme activities in Brucella infection.

Benefits of Zataria multiflora Boiss in Experimental Model of Mouse Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic condition of the intestine with unknown etiology involving multiple immune, genetic and environmental factors. We were interested to examine the effect of total extract from Zataria multiflora Boiss, a folk medicinal plant on prevention and treatment of experimental IBD. Z. multiflora was administered (400, 600, 900 p.p.m.) through drinking water to IBD mice induced by intrarectal administration of acetic acid. Prednisolone was used as the standard drug for comparison. Biochemical, macroscopic and microscopic examinations of colon were performed. Biochemical evaluation of inflamed colon was done using assay of myeloperoxidase (MPO) activity and thiobarbituric acid reactive substances (TBARS) concentration as indicators of free radical activity and cell lipid peroxidation. The activity of MPO and lipid peroxidation products (TBARS) increased in acetic acid-treated groups while recovered by pretreatment of animals with Z. multiflora (400–900 p.p.m.) and prednisolone. Z. multiflora (600 and 900 p.p.m.) and prednisolone-treated groups showed significantly lower score values of macroscopic and microscopic characters when compared with the acetic acid-treated group. The beneficial effect of Z. multiflora (900 p.p.m.) was comparable with that of prednisolone. The antioxidant, antimicrobial and anti-inflammatory potentials of Z. multiflora might be the mechanisms by which this herbal extract protects animals against experimentally induced IBD. Proper clinical investigation should be carried out to confirm the activity in human.

Protection by Ziziphora clinopoides of acetic acid-induced toxic bowel inflammation through reduction of cellular lipid peroxidation and myeloperoxidase activity

Inflammatory bowel disease (IBD) is a chronic condition of the intestine with unknown etiology involving multiple immune, genetic and environmental factors. We were interested in examining the effect of a total extract from Ziziphora clinopoides, an Iranian folk herbal medicine, in the prevention and control of experimental mouse IBD. Z. clinopoides was administered (75, 150, 300 mg/kg) through drinking water to mice, which dispensed a toxic dose of acetic acid intrarectally. Prednisolone was used as the standard drug for comparison. Biochemical, macroscopic and microscopic examinations of the colon were performed. Biochemical evaluation of the inflamed colon was carried out using assays of myeloperoxidase (MPO) activity and thiobarbituric acid reacting substances (TBARS) as indicators of free radical activity and cellular lipid peroxidation. Results indicated that the activity of MPO and lipid peroxidation products (TBARS) increased in acetic acid-treated groups, while recovered by pretreatment of animals with Z. clinopoides (75-300 mg/kg) and prednisolone. All doses of Z. clinopoides and prednisolone-treated groups showed significant lower score values of macroscopic and microscopic characters when compared to the acetic acid-treated group. The beneficial effect of Z. clinopoides (300 mg/kg) was comparable to that of prednisolone. It is concluded that Z. clinopoides inhibits acetic acid toxic reactions in the mouse bowel through inhibition of cellular oxidative stress. Proper clinical investigation should be carried out to confirm the same activity in human.

Chronic treatment of DA-8159, a new phosphodiesterase type V inhibitor, attenuates endothelial dysfunction in stroke-prone spontaneously hypertensive rat

This study examined the effects of chronic treatment of a new phosphodiesterase type 5 inhibitor, DA-8159, on endothelial dysfunction in stroke-prone spontaneously hypertensive rats (SHR-SP). Six-week-old male SHR-SP were divided into 4 groups; vehicle control, DA-8159 1, 3, and 10 mg/kg/day. During a 32-week experimental period, the animals were administered DA-8159 orally and fed a 4% NaCl-loaded diet. The systolic blood pressure was measured every two weeks throughout the experimental period using the tail-cuff method. At the end of experiments, the vascular function (acetylcholine-induced vasodilation) in the endothelium-intact aortic rings was investigated. In addition, the mortality, the left ventricular hypertrophy index, the plasma parameters and the incidence of a cerebral infarction were assessed. In the DA-8159 treated-rats, the vascular reactivity improved significantly in a dose-dependent manner. Although DA-8159 did not alter the elevation of the systolic blood pressure directly, the 3 and 10 mg/kg/day DA-8159 treatment delayed the early death caused by stroke. DA-8159 significantly reduced the left ventricular heart weight/body weight ratio compared with the vehicle control group. Furthermore, the DA-8159 treatment significantly increased the plasma nitric oxide, cGMP, and the total antioxidative status. The DA-8159 treatment also reduced the occurrence of stroke-associated cerebral damage. These results indicate that DA-8159 can ameliorate an endothelial dysfunction-related vascular injury. Therefore, pharmacological intervention aimed at attenuating an endothelial dysfunction is important and might be useful in both preventing and treating endothelial dysfunction-related complications.

Influence of static magnetic field on cadmium toxicity: study of oxidative stress and DNA damage in rat tissues

In the present study, we investigated the effect of co-exposure to static magnetic field (SMF) and cadmium (Cd) on the biochemical parameters, antioxidant enzymes activity and DNA damage in rat tissues. Animals were treated with cadmium (CdCl(2), 40mg/L, per os) in drinking water during 4 weeks. Cd treatment induced an increase of plasma lactate dehydrogenase (LDH) and transaminases levels. Moreover, Cd treatment increased malondialdehyde (MDA) and 8-oxodGuo levels in rat tissues. However, the antioxidant enzymes activity such as the glutathione peroxidase (GPx), catalase (CAT) and the superoxide dismutase (SOD) were decreased in liver and kidney, while we noted a huge increase of hepatic and renal cadmium content. Interestingly, the combined effect of SMF (128mT, 1h/day during 30 consecutive days) and Cd (40mg/L, per os) decreased the GPx and CAT activities in liver compared to cadmium treated group. However, the association between SMF and Cd failed to alter transaminases, MDA and 8-oxodGuo concentration. Cd treatment altered antioxidant enzymes and DNA in liver and kidney of rats. Moreover, SMF associated to Cd disrupt this antioxidant response in liver compared to Cd-treated rats.

Hemodynamic effects of combined sildenafil and L-arginine during acute pulmonary embolism-induced pulmonary hypertension

Sildenafil attenuates acute pulmonary embolism-induced pulmonary hypertension. However, the hemodynamic effects of sildenafil in combination with other vasodilators during acute pulmonary embolism have not been examined yet. In the present study, we examined the hemodynamic effects of combined sildenafil (0.25 mg/kg, i.v.) and L-arginine (100, 200, 500, and 1000 mg/kg/h, i.v.) in an anesthetized dog model of acute pulmonary embolism. Plasma nitrite/nitrate (NO(x)) and cGMP concentrations were determined using an ozone-based chemiluminescence assay and a commercial enzyme immunoassay, respectively. We found that L-arginine alone did not attenuate acute pulmonary embolism-induced pulmonary hypertension. However, significant decreases in mean pulmonary artery pressure were observed 30, 45, 60, and 75 min after the administration of sildenafil alone or after the combined administration of sildenafil and L-arginine (all P < 0.05). No significant differences among groups were observed in the respiratory parameters. While L-arginine significantly increased NO(x) concentrations, cGMP concentrations increased only when sildenafil was administered (all P < 0.05). These results suggest that while sildenafil attenuates acute pulmonary embolism-induced pulmonary hypertension, L-arginine does not enhance the beneficial hemodynamic effects of sildenafil. In addition, these findings suggest that stimulation of NO synthesis with L-arginine during acute pulmonary embolism does not produce beneficial effects.

Total antioxidant capacity and levels of epidermal growth factor and nitric oxide in blood and saliva of insulin-dependent diabetic patients

BACKGROUND

The aim of this study was to examine how type 1 diabetic patients have altered levels of lipid peroxidation, antioxidant defense, NO and EGF in their plasma and saliva. We tested the differences in lipid peroxidation level, antioxidant power, and concentrations of epidermal growth factor (EGF) and nitric oxide (NO) in saliva and blood of type 1 diabetic subjects in comparison to healthy control subjects.

METHODS

Nineteen subjects with type 1 diabetes mellitus and 19 healthy age- and sex-matched control subjects were included in the study. Blood and saliva samples were obtained and analyzed for thiobarbituric reactive substances (TBARS) as a marker of lipid peroxidation, ferric reducing ability (total antioxidant power), EGF and NO levels.

RESULTS

TBARS levels did not show a significant difference between the two groups. Analysis of antioxidant power revealed that saliva and plasma of diabetic patients had more antioxidant power (p <0.01) than the healthy control population (107 +/- 10.35 vs. 11.14 +/- 4.66 and 192 +/- 12.3 vs. 142 +/- 15.2 mmol/L, respectively). Concentration of EGF was increased (p <0.01) in saliva whereas it was reduced (p <0.01) in plasma of diabetic patients in comparison to those of healthy subjects (2423 +/- 322 vs. 1513 +/- 341 and 125 +/- 14 vs. 346 +/- 60 pg/mL, respectively). NO level increased in both saliva and plasma of diabetic patients in comparison to those of healthy subjects (46.61 +/- 7 vs. 72.89 +/- 13 and 62.11 +/- 4.6 vs. 76.25 +/- 5 micromol/L, respectively). Blood HbA1c (%) of patients was significantly higher than that of controls (8.3 +/- 0.32 vs. 5.4 +/- 0.24, p <0.01).

CONCLUSIONS

Existence of increased total antioxidant power in the presence of normal lipid peroxidation in plasma and saliva of type 1 diabetic patients indicates the existence of oxidative stress. Increased salivary EGF and NO levels in association with elevated TAOP is interesting and should be further studied.

Effects of pentoxifylline on oxidative stress and levels of EGF and NO in blood of diabetic type-2 patients; a randomized, double-blind placebo-controlled clinical trial

BACKGROUND

As oxidative stress contributes to both progression and pathologic complications of diabetes and effective therapeutic strategies to prevent or delay the damage remain limited, the aim of the present study was to assess the efficacy of pentoxifylline in reducing of oxidative stress. Since there is a relationship between nitric oxide (NO), epidermal growth factor (EGF) and oxidative stress, we measured the effect of this drug on these parameters in comparison to placebo.

METHODS

Thirty-nine patients with type-2 diabetes mellitus were randomized in a double blind, placebo-controlled clinical trial to receive either pentoxifylline 400 mg four times a day or placebo for 14 days. Blood samples were obtained at baseline and at the end of the study. Samples were analyzed for thiobarbituric reactive substances (TBARS) as a marker of lipid peroxidation, ferric reducing ability (total antioxidant power, TAP), EGF and NO levels.

RESULTS

Pentoxifylline in comparison to placebo was effective (P < 0.05) in reduction of lipid peroxidation in plasma of the patients without significant effects on TAP, levels of EGF and NO in plasma.

CONCLUSION

Adding of pentoxifylline to drug regimen of diabetic type-2 patients can be helpful. Exact mechanism of action of pentoxifylline in reduction of blood lipid peroxidation remains to be elucidated.

The Effect of Sildenafil on Pulmonary Embolism-Induced Oxidative Stress and Pulmonary Hypertension

Acute pulmonary embolism (APE) is a major cause of pulmonary hypertension and death. We examined the effects of sildenafil on the hemodynamic changes caused by APE in anesthetized dogs. Sham-operated dogs (n = 3) received only saline. APE was induced by stepwise IV injections of 300 mum microspheres in amounts adjusted to increase mean pulmonary artery pressures by 20 mm Hg. Hemodynamic evaluation was performed at baseline, after APE was induced, and then after sildenafil 0.25 mg/kg (n = 8), or sildenafil 1 mg/kg + 0.3 mg . kg(-1) . h(-1) (n = 8) or saline (n = 9) infusions were started. Similar experiments were conducted to examine the effects of sildenafil in rat isolated perfused lung preparation. Plasma thiobarbituric acid reactive species were also determined in both studies to measure oxidative stress. Both doses of sildenafil reduced mean pulmonary artery pressures in dogs by approximately 8 to 16 mm Hg (both P < 0.05) and attenuated the increase in oxidative stress after APE. Mean arterial blood pressure remained unaltered after both doses of sildenafil. Sildenafil produced similar effects after APE in rat isolated perfused lung preparation. These findings indicate that IV sildenafil can selectively attenuate the increases in mean pulmonary artery pressures after APE, possibly through antioxidant mechanisms.

On the relation of nitric oxide to nifedipine-induced gingival hyperplasia and impaired submandibular glands function in rats in vivo

Calcium-channel blockers such as nifedipine could be associated with gingival overgrowth. The aim of this study was to examine the role of nitric oxide (NO) on nifedipine-induced gingival hyperplasia along with submandibular secretory function in rats. Animals in divided groups received nifedipine (250 mg/kg diet) alone and in combination with L-arginine (2.25% w/v) or N(omega)-nitro-L-arginine methyl ester (L-NAME) (0.7% w/v) in drinking water for 20 days. Controls received only tap water. Pure submandibular saliva was collected intraorally by micropolyethylene cannula and the mandibular gingiva was examined by means of dissecting microscope for signs of redness, thickness, inflammation and exuda. Twenty-day nifedipine treatment induced gingival hyperplasia accompanied with reduced salivary flow rate and concentrations of total protein, epidermal growth factor (EGF) and calcium in comparison with controls. Co-treatment of animals with nifedipine and L-arginine protected from gingival hyperplasia and retained flow rate, and concentrations of total protein, EGF and calcium in normal levels. Co-treatment of animals with nifedipine and L-NAME potentiated nifedipine-induced gingival hyperplasia and reductions in flow rate and concentrations of total protein, EGF, and calcium. It is concluded that nifedipine-induced gingival hyperplasia is associated with salivary dysfunction. Activation of cGMP-dependent positive signal-transduction mechanisms in salivary glands might be the mechanism for protective effects of NO against nifedipine-induced gingival hyperplasia.