Electroacupuncture of scalp acupoint alleviates cerebral ischemic inflammatory injury by down-regulating RORγt and promoting balance of IL-17A+Th17/FOXP3+Treg in MCAO rats

OBJECTIVES

To observe the effect of electroacupuncture (EA) of scalp acupoint (Dingnieqian-xiexian, MS6) on expression of retinoid-related orphan receptor γT (ROR γ t), interleukin (IL)-17A, IL-10, transfor-ming growth factor-β1 (TGF-β1), IL-6, IL-21, and IL-17A+ Thelper cells(Th) 17 and forkhead transcription factor P3 (FOXP3)+ regulatory T cells (Treg) differentiation of ischemic cortex in ischemic stroke rats, so as to explore its molecular mechanisms underlying relief of inflammatory injury of ischemic stroke.

METHODS

A total of 120 male SD rats were randomly assigned to sham operation, model, EA, inhibitor, agonist and EA+agonist groups, with 15 rats in each group. The ischemic stroke model was established by occlusion of the left middle cerebral artery according to Longa's methods. For rats of the EA group and EA+agonist group, EA (2 Hz/100 Hz, 1 mA) was applied to bilateral MS6 for 30 min, once daily for 7 days. Rats of the inhibitor group received intraperitoneal injection of solution of SR1001 (RORγt inhibitor) (2.5 mg/mL, 10 mg/kg), once daily for 7 days. Rats of the agonist and EA+agonist groups received intraperitoneal injection of solution of SR1078 (RORγt agonist) (5 mg/mL, 5 mg/kg) before EA, once daily for 7 days. Rats of the sham operation and model groups were grabbed and fixed in the same way with the other groups. The Zea-longa's score, modified neurological severity score (mNSS) and the neurobehavioral score were assessed before and after the intervention. At the end of experiments, the ischemic cortex tissue was collected. The 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining was used to detect the volume of cerebral infarction. The expression of RORγt mRNA was detected by real-time quantitative PCR；the protein expression levels of RORγt, IL-17A, IL-10 and TGF-β1 were detected by Western blot；the immunoactivity of IL-6 and IL-21 were detected by immunohistochemistry；the fluorescence areas of IL-17A+Th17 and FOXP3+Treg cells were measured by immunofluorescence and their ratio was calculated in the tissue of ischemic cortex.

RESULTS

Relevant to the sham operation group, the model group had a significant increase in the Zea-Longa's score, mNSS score, neurobehavioral score, cerebral infarct volume, expression levels of RORγt mRNA and protein, IL-17A protein, IL-6 and IL-21 immunoactivity, IL-17A+Th17 immunofluorescence intensity, and the ratio of IL-17A+Th17/FOXP3+Treg (P<0.01), and an obvious decrease in the expression levels of TGF-β1 and IL-10 proteins and FOXP3+Treg immunofluorescence intensity (P<0.01). In contrast to the model group, both EA and inhibitor groups had a significant decrease in the Zea-Longa's score, mNSS score, neurobehavioral score, cerebral infarct volume, expression levels of RORγt mRNA and protein, IL-17A protein, IL-6 and IL-21 immunoactivity, IL-17A+Th17 immunofluorescence intensity, and the ratio of IL-17A+Th17/FOXP3+Treg (P<0.01, P<0.05), and a marked increase in the expression levels of TGF-β1 and IL-10 proteins and FOXP3+Treg immunofluorescence intensity (P<0.05, P<0.01), while the above indicators of the agonist group were all reversed (P<0.01, P<0.05). Comparison between the agonist and EA+agonist groups showed that the Zea-Longa's score, mNSS score, neurobehavioral score, cerebral infarct volume, expression levels of RORγt mRNA and protein, IL-17A protein, IL-6 and IL-21 immunoactivity, IL-17A+Th17 immunofluorescence intensity, and the ratio of IL-17A+Th17/FOXP3+Treg were significantly lower (P<0.01, P<0.05), and the expression of TGF-β1 and IL-10 proteins and FOXP3+Treg immunofluorescence intensity were obviously higher (P<0.01, P<0.05) in the EA+agonist group than in the agonist group, suggesting that EA intervention can effectively weaken the effects of RORγt agonist.

CONCLUSIONS

EA of scalp acupoint MS6 can effectively improve the neurological function, behavior reaction and reduce cerebral infarct volume in ischemic stroke rats, which may be associated with its functions in down-regulating the expression of RORγt and promoting the balance of IL-17A+Th17/FOXP3+Treg to alleviate inflammatory injury after ischemic stroke.

Suppression of cAMP/PKA/CREB signaling ameliorates retinal injury in diabetic retinopathy

The blood-retinal barrier (BRB), homeostasis, neuronal integrity, and metabolic processes are all directly influenced by Müller cells, the most important retinal glial cells. We isolated primary Müller cells from Sprague-Dawley (SD) neonatal rats and treated them with glucose at varying doses. CCK-8 was used to quantify cellular viability, and a TUNEL assay was performed to detect cell apoptosis. ELISA, immunofluorescence, and western blotting were used to assess cAMP/PKA/CREB signaling, Kir4.1, AQP4, GFAP, and VEGF levels, respectively. H&E staining was used to examine histopathological alterations in diabetic retinopathy (DR)-affected retinal tissue in rats. As glucose concentration increases, gliosis of Müller cells became apparent, as evidenced by a decline in cell activity, an increase in apoptosis, downregulation of Kir4.1 level, and overexpression of GFAP, AQP4, and VEGF. Treatments with low, intermediate, and high glucose levels led to aberrant activation of cAMP/PKA/CREB signaling. Interestingly, blocking cAMP and PKA reduced high glucose-induced Müller cell damage and gliosis by a significant amount. Further in vivo results suggested that cAMP or PKA inhibition significantly improved edema, bleeding, and retinal disorders. Our findings showed that high glucose exacerbated Müller cell damage and gliosis via a mechanism involving cAMP/PKA/CREB signaling.

Ferroptosis—A Novel Mechanism With Multifaceted Actions on Stroke

As a neurological disease with high morbidity, disability, and mortality, the pathological mechanism underlying stroke involves complex processes such as neuroinflammation, oxidative stress, apoptosis, autophagy, and excitotoxicity; but the related research on these molecular mechanisms has not been effectively applied in clinical practice. As a form of iron-dependent regulated cell death, ferroptosis was first discovered in the pathological process of cancer, but recent studies have shown that ferroptosis is closely related to the onset and development of stroke. Therefore, a deeper understanding of the relationship between ferroptosis and stroke may lead to more effective treatment strategies. Herein, we reviewed the mechanism(s) underlying the onset of ferroptosis in stroke, the potential role of ferroptosis in stroke, and the crosstalk between ferroptosis and other pathological mechanisms. This will further deepen our understanding of ferroptosis and provide new approaches to the treatment of stroke.

[Effects of p-Phenylene diamine on liver and kidney functions of occupational exposed workers]

Objective: To study the effect of p-phenylenediamine (PPD) on liver and kidney function in occupational exposed workers. Methods: Workers in a hair dye production enterprise which used p-phenylenediamine as a raw material for production were selected as the main research population. Then we conducted a questionnaire survey on the basic conditions of workers and conducted occupational health checkups on general health status, liver and kidney function. Occupational health examination assessment results were tested in Taizhou Cancer Hospital. All data was built using EpiData 3.1 software, and statistical analysis was performed using software SPSS 20.0. Results: The liver function indicators including direct bilirubin, prealbumin, total protein, and white protein, globulin, aspartate aminotransferase, glutamyl transpeptidase, and total bilirubin in the workers exposed to high concentration of PPD were at high normal values, and these indicators were significantly different from low PPD concentration group (P<0.05) . The serum creatinine and serum uric acid in the renal function index were significantly higher in workers exposed to PPD than in workers exposed to low concentrations and in the control group (P<0.05) . Conclusion: Occupational exposed to PPD may have a hazard to the workers' liver and kidney function. Long-term occupational exposure to PPD may lead to increased cumulative exposure of workers, which may cause potential chronic liver and kidney damage in occupationally exposed populations.

Melatonin ameliorates vascular endothelial dysfunction, inflammation, and atherosclerosis by suppressing the TLR4/NF-κB system in high-fat-fed rabbits

Vascular endothelial dysfunction (VED) and inflammation contribute to the initiation and progression of atherosclerosis. Melatonin (MLT) normalizes lipid profile, improves endothelial function, and possesses anti-inflammatory properties. However, the precise mechanisms are still unclear. This study investigated whether MLT could ameliorate VED, inflammation, and atherosclerosis by suppressing the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) system in high-fat-fed rabbits. Rabbits were randomly divided into three groups that received a standard diet (control group), high-cholesterol diet (atherosclerosis group), or high-cholesterol diet plus 10 mg/kg/day MLT (MLT group) for 12 wk. After treatment, high-fat diet significantly increased serum lipid and inflammatory markers in rabbits in atherosclerosis group compared with that in control group. In addition, high-fat diet also induced VED and typical atherosclerotic plaque formation and increased intima/media thickness ratio, which were significantly improved by MLT therapy as demonstrated in MLT group. Histological and immunoblot analysis further showed that high-fat diet enhanced the expressions of TLR4, myeloid differentiation primary response protein (MyD88), and NF-κB p65, but decreased inhibitor of NF-κB (IκB) expression. By contrast, MLT therapy decreased the expressions of TLR4, MyD88, and NF-κB p65 and increased IκB expression. This study has demonstrated that MLT ameliorates lipid metabolism, VED, and inflammation and inhibits the progression of atherosclerosis in high-fat-fed rabbits. Moreover, our study indicates for the first time that suppression of the TLR4/NF-κB system in local vasculature with atherosclerotic damage is important for the protective effects of MLT.

Endostatin Gene Therapy for Endometriosis in Rats

Objective:

Endostatin gene therapy for endometriosis was studied in an experimental autotransplantation model in rats.

Methods:

Endometriotic lesions were transfected by intralesional injection of the plasmid lipofectamine-endostatinpBud (group 1), lipofectamine-pBud (empty vector; group 2) or phosphatebuffered saline (group 3). Endostatin mRNA and protein levels in lesions were evaluated by quantitative real-time reverse transcription-polymerase chain reaction and Western blot analysis. Endostatin and vascular endothelial growth factor (VEGF) protein levels in serum, and microvessel density (MVD) and matrix metalloproteinase (MMP)-2 protein levels in endometriotic lesions, were also determined.

Results:

Lipofectamine- endostatin-pBud injection increased endostatin mRNA and protein levels in lesions. Lesions were significantly smaller, and serum VEGF levels significantly lower, in group 1 versus controls. Serum VEGF was significantly and negatively correlated with serum endostatin. In group 1, MMP-2 levels and MVD were significantly lower versus controls. MMP-2 level was negatively correlated with endostatin.

Conclusions:

Gene therapy with endostatin appears to be an effective treatment for endometriosis. Restoration of endostatin gene expression by gene transfer in vivo might be a potential gene therapy approach for human endometriosis.

In vitro and in vivo antimicrobial activity of Xenorhabdus bovienii YL002 against Phytophthora capsici and Botrytis cinerea

AIMS

Developing new bio-agents to control plant disease is desirable. Entomopathogenic bacteria Xenorhabdus spp. have potential antimicrobial activity in agriculture. This work was conducted to evaluate the antimicrobial activity of Xenorhabdus bovienii YL002 on plant pathogenic fungi and oomycete in vitro and the efficiency of this strain to reduce the in vivo incidence of grey mould rot on tomato plants caused by Botrytis cinerea and leaf scorch on pepper plants caused by Phytophthora capsici.

METHODS AND RESULTS

The antimicrobial activity of X. bovienii YL002 was firstly determined on in vitro plant pathogenic fungi and oomycete and then on tomato fruits and plants infected with B. cinerea and pepper plants infected with P. capsici. The cell-free filtrate of X. bovienii YL002 exhibited highest inhibition effects (>98%) on mycelia growth of P. capsici and B. cinerea. The 50% inhibition concentration (EC₅₀) of the methanol-extracted bioactive compounds (methanol extract) of the cell-free filtrate against P. capsici and B. cinerea were 164·83 and 42·16 μg ml⁻¹. The methanol extract also had a strong effect on the spore germination of P. capsici and B. cinerea, with a EC₅₀ of 70·38 and 69·33 μg ml⁻¹, respectively. At 1000 μg ml⁻¹, the methanol extract showed a therapeutic effect of 70·82% and a protective effect of 77·4% against B. cinerea on tomato plants compared with the control. The methanol extract also showed potent effect against P. capsici, with a therapeutic effect of 68·14% and a protective effect of 65·46% on pepper plants compared with the control.

CONCLUSIONS

Xenorhabdus bovienii YL002 produces antimicrobial compounds with strong activity on plant pathogenic fungi and oomycete and has the potential for controlling grey mould rot of tomato plants and leaf scorch of pepper and could be useful in integrated control against diverse plant pathogenic fungi and oomycete.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study showed the potential that X. bovienii YL002 can be used to control the grey mould rot caused by B. cinerea on tomato plants and leaf scorch caused by P. capsici on pepper plants with the objective to reduce treatments with chemical fungicides.

Evaluation of intestinal absorption of ginsenoside Rg1 incorporated in microemulison using parallel artificial membrane permeability assay

In the present study, ginsenoside Rg(1) (Rg(1)), a naturally occurring drug which is hardly absorbed in gastrointestinal (GI) tract due to its high hydrophilicity and low membrane permeability, was incorporated in different compositions of water-in-oil microemulsions (MEs). And parallel artificial membrane permeability assay (PAMPA) that have been mainly utilized for the evaluation of in vitro permeability of early drug candidates was introduced in present study, as well as rat in vivo pharmacokinetics and in vitro permeability measurements, to investigate the effect of w/o ME on Rg(1) absorption. Correlation between various models as mentioned above was further performed to estimate the feasibility of PAMPA in the application of pharmaceutical preparation studies. After being administrated intraduodenally to rats, most of MEs can enhance the intestinal absorption of Rg(1) to various extents with relative bioavailability (F(re)) ranging from 268 to 1270% using drug solution as control. This enhanced absorption of Rg(1) may be related to its increased membrane permeability induced by ME as exhibited in the PAMPA and rat in vitro permeability measurements. Meanwhile, rat in vivo pharmacokinetics-PAMPA correlation (r(2)=0.6082) is significant (p<0.05) for ME, representing a potential prospect for the application of PAMPA in the study of pharmaceutical preparation in some conditions.

Transport of aripiprazole across Caco-2 monolayer model

This study aimed to investigate the transport characteristics of aripiprazole. A human intestinal epithelial cell model Caco-2 cell in vitro cultured had been applied to study the transport of aripiprazole. The effects of time, concentration of donor solutions, pH, temperature and P-glycoprotein inhibitor on the transport of aripiprazole were investigated. The determination of aripiprazole was performed by HPLC. It is concluded that aripiprazole is transported through the intestinal mucosa via a passive diffusion mechanism primarily, coexisting with a carrier-mediated transport. The transport of aripiprazole is positively correlated to transport time, pH, and temperature. Papp increased with donor concentrations up to 10 microg x mL(-1), and then decreased for higher concentrations. The P-glycoprotein inhibitor cyclosporine A significantly enhanced the transport amount of aripiprazole.

[Physicochemical stability and purification technology of caffeic acid tetramer from Arnebia euchroma]

OBJECTIVE

To purify caffeic acid tetramer (CAT) with macroporous resin on the basis of its fundamental physicochemical stability research.

METHOD

The changes of CAT content were compared by HPLC method before and after the purification process, or while other conditions were altered.

RESULT

LK001 was the best one among 7 kinds of macroporous resin in regard of purifying ability. The optimum absorbing technology was the solution concentration at 10 g x L(-1), pH at 4.5, and the flow rate at 3 BV x h(-1). The best eluting technology was 45% ethanol as eluting agent, pH at 5.0, eluting volume at 50 mL after applying super-purified water and 20% ethanol. The yield of product was 3. 6 percent, and the active compound CAT was 58 percent in the product.

CONCLUSION

Macroporous resin LK001 is effective in enriching CAT from the crude extracts, thus this method of purification is advisable.

[Preparation, characterization of paclitaxel-loaded Pluronic P105 polymeric micelles and in vitro reversal of multidrug resistant tumor]

Drug delivery system (DDS) is a novel approach to overcome multidrug resistance (MDR) in tumors nowadays. This work was designed to investigate a new micellar delivery system for in vitro reversal of resistant ovarian tumor cells, based on a nonionic triblock copolymer Pluronic P105 and paclitaxel (PTX). The PTX-loaded polymeric micelles (P105/PTX) were prepared by thin film-hydration methods. Based on the results of single factor experiments, the P105/PTX micelle formulation was optimized by employing the central composite design-response surface methodology. The physico-chemical properties of the P105/PTX micelles were characterized, including micelle size, drug loading coefficient, in vitro release behavior, etc. The cytotoxicity of the P105/PTX micelles was assessed against human ovarian tumor cell line, SKOV-3/PTX, by a standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay. In order to understand the possible mechanism of Pluronic effects in resistant tumor cells, cellular uptake study of micellar PTX or Rhodamine-123 (R-123) was also carried out. The results showed that the micelle size was about 24 nm with drug loading coefficient of 1.1% and PTX concentration of 700 microg x mL(-1). The cumulative release amount of PTX from the P105/PTX micelles was only 45.4% in 6 h (P < 0.05) and 79.6% in 24 h, whereas Taxol injection in 6 h released 95.2% PTX. The IC50 values of the P105/PTX micelles and Taxol injection against SKOV-3/PTX were 1.14 and 5.11 microg x mL(-1), and resistance reversion index (RRI) was 9.65 and 2.15, respectively. The micellar PTX or R-123 exhibited a significant increase in cellular uptake in resistant SKOV-3/PTX cells compared with free PTX or R-123. These results indicated that PTX could effectively be solubilized by Pluronic P105 block copolymers via thin film-hydration process and formulation optimization, producing nano-scale polymeric micelles with sustained release property in vitro. The P105/PTX micelles were effectively able to reverse resistance to PTX in SKOV-3/PTX tumor cells compared with Taxol injection or free PTX solution, and the enhanced cytotoxicity in the resistant SKOV-3/PTX cell was related to the improved cellular uptake of PTX by Pluronic P105 copolymers.

[Comparison between the characteristics of absorption and pharmacokinetic behavior of ginsenoside Rg1 and ginsenoside Rb, of Panax notoginseng saponins]

To compare the characteristics of absorption and pharmacokinetic behavior of ginsenoside Rg1 (Rg1) with ginsenoside Rb1 (Rb1) of panax notoginseng saponins (PNS), bile excretion of both Rg1 and Rb1 were studied after i.v. and i.g. of PNS solution. Plasma protein binding ratios were studied using equilibrium dialysis method, and referred to pharmacokinetic parameters. It shows that (61.48 +/- 18.30)% dose of Rg1 and (3.94 +/- 1.49)% dose of Rb1 were separately excreted into bile 10 hours after i.v. administration (PNS 50 mg x mL(-1)), and (0.91 +/- 0.51)% dose of Rg1 and (0.055 +/- 0.02)% dose of Rb1 were excreted into bile 12 hours after i.g. administration (PNS 1 500 mg x mL(-1)). Plasma protein binding degrees of Rg1 and Rb1 were 6.56% - 12.74% and 80.1% - 89.69%, respectively. Stomach, intestinal and hepatic throughput efficiency (F(S), F1 and F(H)) for Rg1 were 49.85%, 13.05%, 50.56%, respectively, and 25.82%, 4.18%, 65.77% for Rb1. Therefore, poor intestinal absorption is a primary reason for the low bioavailability of both Rg1 and Rb1. Rg1 possesses relatively high bile excretion and low plasma protein binding rate, in contrast, Rb1 possesses low bile excretion and high plasma protein binding rate. Membrane permeability and elimination rate of Rb1 were lower than that of Rg1, meanwhile, longer MRT and bigger AUC could be found for Rb1.

Biodistribution in mice and severity of damage in rat lungs following pulmonary delivery of 9-nitrocamptothecin liposomes

This study was designed to investigate in vitro release, in vivo tissue distribution and the damage to the lungs of 9-nitrocamptothecin (9-NC) liposomes. In vitro release of 9-NC from liposomes was carried out in phosphate buffer saline solution (PBS) pH 7.4. The tissue distribution of 9-NC liposomes and 9-NC solution was determined after pulmonary delivery to mice. The tissue distribution of 9-NC liposomes after intravenous administration was also studied. The changes of pulmonary edema index and histology of lungs in rats were investigated to evaluate the severity of the damage after pulmonary delivery. The results showed that 9-NC was continuously released from liposomes in PBS pH 7.4 for 24h at 37 degrees C. After pulmonary delivery, the mean residence time (MRT) of 9-NC liposomes in the lungs was 3.4 times as long as that of 9-NC solution and the total AUC0-t of all tissues in mice of the liposomes was 2.2-fold higher than that of the solution, indicating that the liposomes had sustained-release characteristics. Following intravenous administration and pulmonary delivery, the targeting efficiency (Te) to the lung of 9-NC liposomes was 0.14 and 2.02, respectively, which showed that intratracheal instillation can deliver the drug mainly to the lung and decrease the accumulation of the drug in other tissues at different concentrations. The pulmonary edema index and the histological changes of the lungs in 9-NC liposome group were significantly different from those in 9-NC solution group. The lung damage by liposomes was less severe than that by solution. Pulmonary delivery of 9-NC liposomes could directly deliver the drug to the lung and make the drug accumulate in the lung with sustained-release characteristics, changing the disposition behavior in vivo, decreasing the toxic and side effects on other tissues and reduce the severity of damage to lungs following intratracheal instillation.

Pharmacokinetics and biodistribution of polymeric micelles of paclitaxel with Pluronic P123

AIM

To investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of a novel polymeric micellar formulation of paclitaxel (PTX) with Pluronic P123.

METHODS

The polymeric micelles of paclitaxel with Pluronic P123 were prepared by a solid dispersion method. The characteristics of micelles including particle size distribution, morphology and in vitro release of PTX from micelles were carried out. PTX-loaded micellar solutions were administered through the tail vein to healthy Sprague-Dawley rats and Kunming strain mice to assess the pharmacokinetics and tissue distribution of PTX, respectively. Taxol, the commercially available intravenous formulation of PTX, was also administered as control.

RESULTS

By using a dynamic light scattering sizer and a transmission electron microscopy, it was shown that the PTX-loaded micelles had a mean size of approximately 25 nm with narrow size distribution and a spherical shape. PTX was continuously released from Pluronic P123 micelles in release medium containing 1 mol/L sodium salicylate for 24 h at 37 centigrade degree. In the pharmacokinetic assessment, t(1/2beta) and AUC of micelle formulation were 2.3 and 2.9-fold higher than that of Taxol injection. And the PTX-loaded micelles increased the uptake of PTX in the plasma, ovary and uterus, lung, and kidney, but decreased uptake in the liver and brain in the biodistribution study.

CONCLUSION

Polymeric micelles using Pluronic P123 can effectively solubilize PTX, prolong blood circulation time and modify the biodistribution of PTX.

[Mechanism of oral absorption of panaxnotoginseng saponins]

AIM

To study the mechanism of absorption after oral administration of panaxnotoginseng saponins (PNS).

METHODS

Caco-2 cells and rat models were applied to evaluate the degradation of both ginsenoside Rb1 (Rb1) and ginsenoside Rg1 (Rg1) in PNS in gastrointestinal lumen, and the transport mechanism of PNS across the intestinal mucosa, and the barrier function of stomach, intestine and liver involved in absorption process.

RESULTS

Rb1 and Rg1 proved to be readily eliminated in stomach, but stable in relatively neutral circumstance. Both Rb1 and Rg1 in PNS, especially for Rb1, degraded significantly in the contents of large intestine. However, both of them kept mainly intact in the contents of small intestine. Uptake of both Rb1 and Rg1 by Caco-2 cell monolayer was inhibited at low temperature, but not by cyclosporine A, and the change in the apical pH showed no pronounced effect. Uptake and transport were non-saturable and increased linearly with increasing of concentrations of Rb1 and Rg1 over the range of concentration tested, which indicated a passive transport. There was no significant difference of absorption characteristic between monomer (Rb1 and Rg1) and mixture (PNS). Uptake amount of Rg1 [(1.07 +/- 0.16) microg x mg(-1) (protein)] (C0 = 1 mg x mL(-1)) in Caco-2 cells was a little higher than that of Rb1 [(0.77 +/- 0.03) microg x mg(-1) (protein)] (C0 = 1 mg x mL(-1)). Meanwhile, apparent permeability coefficient of (5.9 +/- 1.0) x 10(-8) cm x s(-1) (C0 = 1 mg x mL(-1)) for Rb1 and (2.59 +/- 0.17) x 10(-7) cm x s(-1) (C0 = 1 mg x mL(-1)) for Rg1 from apical compartment to basolateral compartment predicted an incompletely absorption. Transports of both Rb1 and Rg1 were not influenced by cyclosporine A. The investigation on the pharmacokinetic behavior of Rb1 and Rg1 after different routes of administration to rats showed that the absolute bioavailability after peroral (po), intraduodenal (id), and portal venous (pv) administration is 0.71% , 2.75% and 65.77% respectively for Rb1, and 3.29%, 6.60% and 50.56% respectively for Rg1.

CONCLUSION

Transport across Caco-2 cell monolayer for PNS (include Rb1 and Rg1) is a simple passive diffusion process. No efflux transporters in Caco-2 cells and other components in PNS showed effects on it. The elimination in stomach, large intestine and liver contributed to the low bioavailability of PNS, but the low membrane permeability might be a more important factor dominating the extent of absorption.

Difference in oral absorption of ginsenoside Rg1 between in vitro and in vivo models

AIM

To clarify the cause of poor oral absorption of ginsenoside Rg1 (Rg1), the active ingredient in Panax notoginseng saponins (PNS) used for treating hemorrhage.

METHODS

Caco-2 cell monolayers were used as an in vitro model to study the transport mechanism of Rg1 across the intestinal mucosa. Moreover, the serum concentration-time profiles after peroral (po), intraduodenal (id), portal venous (pv) and tail venous (iv) administration of Rg1 in rats were compared to evaluate the first-pass effects in the stomach, intestine, and liver.

RESULTS

Uptake of Rg1 by Caco-2 cell monolayers was temperature-dependent, but was not influenced by cyclosporin A. The change in the apical pH produced no obvious effect on the uptake of Rg1. The uptake and transport of Rg1 was non-saturable; whereas the flux from the apical compartment to the basolateral compartment (A-B) increased in a linear manner with the increase in concentration, indicating passive transport. An apparent permeability coefficient of (2.59+/-0.17)*10(-7) cm/s (C0=1 mg/mL) predicted incomplete absorption. A significant difference was observed between the po (F(po) was 3.29% at a dose of 1500 mg/kg), id (F(id) was 6.60% at a dose of 1200 mg/kg) and pv (F(pv) was 50.56%) administration methods, and the barrier function of the intestine was more significant than those of the stomach and liver in the absorption process.

CONCLUSION

Elimination in the stomach, large intestine and liver contributed to the low oral bioavailability of Rg1, but low membrane permeability might be a more important factor in determining the extent of absorption.

[Effect of self-microemulsifying system on cell tight junctions]

AIM

To study the effect of negatively charged and positively charged self-microemulsifying systems (SMES) on the cellular tight junction complex was to be investigated at molecular cell level.

METHODS

Human intestinal epithelial Caco-2 cell model was established. Effect of formulations on the transepithelial electrical resistance (TEER) and permeability of the paracellular transport marker mannitol were measured to evaluate the cell integrity. Changes in subcellular localization of the tight junction protein zona occludens 1 (ZO-1) and cytoskeleton protein actin by immunofluorescence were also assessed after treatment of two SMESs in different dilutions.

RESULTS

The TEER of cell monolayers was not markedly affected by negatively charged SMES in different dilutions. The positively charged SMES could significantly decrease the TEER (P < 0.05) in three dilutions. The full recovery of TEER was found after the treatment of lower dilution for 2 h, then cultured for 48 h, while the recovery of TEER was 81.3% of control in 1 : 50 dilution. Two SMESs could enhance the apparent permeability coefficient of mannitol (2.9 - 64.6 folds), which depended on the dilution times. The immunofluorescent results indicated that the distribution of ZO-1 and actin were discrete in cell membrane after the treatment of formulation. Since the positively charged microemulsion could bind to the epithelial cell membrane by electrostatic interaction, the actin of the cells undergone some kind of stress stimulated by the higher concentration of microemulsion was more markedly affected than the negatively charged SMES. Effect of formulations on ZO-1 and actin relied on the dilution.

CONCLUSION

SMES is able to enhance the paracellular transport marker mannitol. The mechanism of opening of tight junctions by SMES might be the change of distribution of ZO-1 and actin.

[Effect of progesterone on the secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9 in human ectopic endometrial stromal cells]

OBJECTIVE

To determine the effect of progesterone on the secretion of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in ectopic endometrial stromal cells.

METHODS

Ectopic endometrial stromal cells were obtained from 17 patients with endometriosis. Endometrial stromal cells were obtained from 12 patients with endometriosis and 14 cases of controls. Ectopic endometrial stromal cells of 15 cases were treated with progesterone. Culture supernatants of these stromal cells were analyzed for MMP-2 and MMP-9 by zymography.

RESULTS

Endometriotic stromal cells released significantly higher levels of MMP-2 and MMP-9 than endometrial stromal cells from women with and without endometriosis. Progesterone at 10(-9) mol/L caused endometriotic stromal cells a significant reduction MMP-2 and MMP-9 levels. When progesterone concentration was increased from 10(-9) mol/L to 10(-7) mol/L, the release of MMP-9 was almost completely inhibited, wherease that of MMP-2 was not completely inhibited.

CONCLUSION

Progesterone may inhibit the secretion of MMP-2 and MMP-9 in ectopic endometrial stromal cells, especially MMP-9.

Sex differentials in perinatal mortality in China and Finland

This study describes patterns of sex differentials in perinatal mortality in China and Finland. The analysis is based on three population-based one-year birth cohorts, one from Qingdao, China, in 1992 and two from Northern Finland in 1966 and 1985-86, comprised of 9,219, 11,422 and 9,207 singletons with at least 28 gestational weeks and 1000 g in birthweight, respectively. Both Finnish cohorts had an excess of male over female perinatal deaths, but in the Chinese cohort girls were more likely to die than boys. The adjusted odds ratio (OR) of perinatal mortality for boys was 1.31 (95 per cent confidence interval [CI] 0.98, 1.78) and 1.57 (95 per cent CI 0.89, 2.78) in the Finnish 1966 and 1985-86 cohorts, respectively, and 0.82 (95 per cent CI 0.55, 1.20) in the Chinese cohort. The corresponding figure for stillbirths in the Chinese was 0.57 (95 per cent CI 0.33, 0.98), which could explain the total excess of female deaths during the perinatal period. Our results suggest that the role of different social and cultural environments on the existing sex differentials in perinatal mortality between the countries needs further evaluation.

[Toxicity of drugs on nasal mucocilia and the method of its evaluation]

Effect of solutions or suspensions of eight drugs including analgin, paracetamol, propafenone hydrochloride, propranolol hydrochloride, ephedrine hydrochloride, gentamycin sulfate, sodium deoxycholate and hydrocortisone on ciliary movement were evaluated with in vitro or in situ toad palate model and scanning electron microscope. In vitro toad palate model: 0.2 ml of test drug solution or suspension was applied to a piece of freshly dissected upper palate of toad. The mucocilia were examined with an optical microscope and the lasting time of ciliary movement was recorded after drug application. The upper palate was rinsed with physiological saline when the ciliary movement stopped. The lasting time of ciliary movement after rinsing was then recorded again. In situ palate model: 0.5 ml of test drug solution or suspension was applied to the upper palate of toad for 30 min, and rinsed with physiological saline. The palate was dissected out and the operation was carried out in a similar manner. The results showed that the in situ toad palate model is a satisfactory method for studying the ciliotoxicity of drugs. The in vitro toad palate model is unsuitable for suspension and gel. The results of the eight drugs revealed that ciliary movement is frequently affected by many drugs and, therefore, care must be taken in developing any nasal dosage form to ensure its least ciliotoxicity.

[Comparison of concentration of piroxicam in blood and local site after two routes of administration]

The systematic and local concentrations of piroxicam after oral and transdermal administration were determined and compared. Mice were randomly grouped, and oral suspensions (0.72 mg.ml-1) or transdermal gels 1 mg.ml-1 were given. Systematic concentration (Cs) and local concentration (C1) of the drug in each mouse were determined by HPLC method. After transdermal administration of 0.25 mg of piroxicam gels Cmax(s) = 8.06 micrograms.ml-1 and AUC(s)0-24(s) = 58.36 micrograms.h.ml-1 were obtained, whereas after oral administration of 0.026 mg.10 g-1 body weight of piroxicam suspensions Cmax(s) was 36.82 micrograms.ml-1 and AUC(s)0-24 was 155.59 micrograms.h.ml-1. The C1/Cs ratio (0.01) through oral route was far lower than the C1/Cs ratio (0.13) through transdermal route. The area under local concentration-time curve (15.85 micrograms.h.ml-1) calculated from transdermal administration was much higher than that from oral administration (1.93 micrograms.h.ml-1). So, it seems to be unreasonable that only serum concentration is taken as a criterion for bioavailability test of piroxicam for local dosage forms, the local drug concentration should also be investigated and evaluated.