Influence of exogenous somatostatin on pancreatic blood flow in normal rats or rats with acute necrotizing pancreatitis

AIM:To investigate the influence of exogenous somatostatin (stilamin) on pancreatic blood flow in normal rats or rats with acute necrotizing pancreatitis (ANP).METHODS:Pancreatic blood flow (PBF) was detected with computerized tissue blood flowmeter and rats with ANP were triggered with sodium taurocholate. Metabolites of eicosanoids in plasma were determined with radioimmunoassay. Other laboratory tests including histopathologic observation under optical or electron microscope were used. RESULTS:There was a significant decrease in PBF in normal rats after stilamin administration in comparison with that before use of the drug. There was significant decrease in PBF after onset of ANP, but, compared with that in ANP group, significant increase was shown in SS(stilamin)+ANP group. Plasma thromboxin-B₂(TXB₂) in ANP group at 6 hours after ANP was significantly higher, with increase of 4.5 times, than that in Sham(sham operated) group while TXB₂, detected each time during the course of ANP, significantly decreased in SS+ANP group. 6-Keto-prostagland in F_1α(6-Keto-PGF_1α) at 6 h after ANP was significantly higher, and the ratio of TXB ₂／6-Keto-PGF_1α, significantly lower in SS+ANP group than that in ANP group. Lessened necrosis of acinar cells, along with much fewer microthrombi in microvessels in SS+ANP group, was shown by pathologic scoring or electron microscope than that in ANP group.CONCLUSION:Administration of exogenous somatostatin leads to the decrease in PBF in physiological setting but it attenuates pancreatic ischemia in SS+ANP group, which may be attributed to correction of abnormal metabolism of eicosanoids, improvement of pancreatic microcirculation and cytoprotection of acinar cells as well.     

Effect of amiodarone and metoprolol on platelet activation,fibrinolytic activity and vasoactive mediators in acute myocardial infarction in rabbits

AIM:To explore the significance of platelet activation, fibrinolytic activity and the changes of vasoactive mediators in acute myocardial infarction in rabbits and the intervention of amiodarone and metoprolol.METHODS:Fifty New Zealand white rabbits were randomly assigned to five groups, ten for each. Group Ⅰ: sham group, group Ⅱ: acute myocardial infarction(AMI) group, group Ⅲ: AMI and lidocaine group, group Ⅳ: AMI and amiodarone group, group Ⅴ: AMI and metoprolol group.The middle point of left ventricular coronary artery was ligated (groupⅡ,Ⅲ, Ⅳ and Ⅴ ) or a sham ligation(group Ⅰ). Four hours later, blood was collected for measuring plasma concentration of TXB₂, 6-Keto-PGF_1α, ET, NO, plasma activity of t-Pa and PAI.After that, the heart was taken out to evaluate the infarction size(IS).RESULTS:Plasma concentration of TXB₂, ET, NO and plasma activity of PAI were significantly higher in groupⅡ,Ⅲ, Ⅳ and Ⅴ than those in group Ⅰ(P＜0.01), but the plasma concentration of 6-Keto-PGF_1α and plasma activity of t-Pa were remarkably lower in groupⅡ,Ⅲ, Ⅳ and Ⅴ than those in group Ⅰ(P＜0.01). There were no difference in plasma concentration of TXB₂, 6-Keto-PGF_1α, t-Pa activity and infarction size in group Ⅱ,Ⅲ and Ⅳ(P＞0.05).Compared to group Ⅱ, plasma concentration of ET, NO and PAI activity were significantly decresed (P＜0.01)in group Ⅳ. Plasma concentration of TXB₂, ET, NO and plasma activity of PAI were significantly lower in groupⅤ than those in group Ⅱ(P＜0.01). Conversely, plasma concentration of 6-Keto-PGF1 and plasma activity of t-Pa were remarkably higher in group Ⅴ than those in group Ⅱ(P＜0.01). The infarction size was remarkly decrease(P＜0.01)in group Ⅴ.CONCLUSIONS:Amiodarone inhibited PAI avtivity, decreased release of ET and NO in AMI in rabbits. Metoprolol inhibited platelet activation, improved fibrinolytic, decreased release of ET and NO, and reduced myocardial infarction size in AMI in rabbits; Lidocaine had no effect above.     

Effect of IL-10 on IL-1β-induced cyclooxygenase-2 expression and prostaglandin E2 release in human mesangial cells

AIM: To investigate the effect of IL-10 on IL-1β-induced prostaglandin E₂(PGE₂) release and cyclooxygenase-2(COX-2) expression in human mesangial cells and to examine whether IL-10 has effect on the biological function of IL-1β.METHODS: The PGE₂ concentration in supernatants of HMC was measured by radioimmunoassay. The COX-2 mRNA and protein were measured by RT-PCR and Western blot, respectively. RESULTS: PGE₂ and COX-2 were significantly increased after treatment with IL-1β(P＜0.01 for both) in cultured human mesangial cells. IL-10 had no effects on basical production of COX-2 and PGE₂(P＞0.05, respectively), while it inhibited IL-1β-elicited PGE₂ production, as well as COX-2 mRNA and protein expression in a concentration-dependent fashion. CONCLUSIONS: These results indicated that IL-10 depressed the IL-1β-induced release of PGE₂ and expression of COX-2. These data suggested that IL-10 could exert anti-inflammatory actions at several levels, not only by inhibiting the production of pro-inflammatory cytokines but also by suppressing their biological function.     

The relationship between the activity of phospholipase A2 and chronic hypoxic pulmonary hypertension

AIM:To study the relationship between the activity of phospholipase A₂ (PLA₂) and chronic hypoxic pulmonary hypertension. METHODS:29 healthy SD rats were randomly divided into normal control group, chronic hypoxic group and hypoxia plus Polidatin (PD) group. The model of rat chronic hypoxic pulmonary hypertension was made by method of intermittent isobaric hypoxia for 21 days. The mean pulmonary arterial pressure (mPAP) was measured by inserting a microcatheter into the pulmonary artery. RESULTS:After exposing hypoxia for 21 days, the mPAP, R/L+S, the PLA₂ activity, TXB₂, MDA in plasma and lung homogenate increased significantly, while 6-k-PGF_1α, SOD decreased significantly. Pretreatment with PD could relieve the changes mentioned above.CONCLUSION:PLA₂ plays an important inducing role through its metabolic products and the interactional radicals in the formation of chronic hypoxic pulmonary hypertension.     

Lipoxin A4 reduces lipopolysaccharide-induced expression of cyclooxygenase 2 and prostaglandin E2 in human bronchial epithelial cells

AIM: To explore the effects of lipoxin A₄ on the expression of cyclooxygenase 2 (COX-2) in human bronchial epithelial cells (HBECs). METHODS: HBECs were incubated with various concentrations (0.1, 1 and 10 mg/L) of lipopolysaccharide(LPS) for 9 h, or 1 mg/L LPS for different time (3 h, 6 h and 9 h). The levels of COX-2 mRNA in HBECs and prostaglandin E₂ (PGE₂) in the culture supernatant were measured. In addition, the HBECs were exposed to lipoxin A₄ at concentration of 0, 100 and 400 μmol/L after stimulated with LPS at concentration of 1 mg/L for 9 h, and the supernatant of the culture cells was collected for determining the content of PGE₂ by ELISA. The cells were also harvested, and the mRNA and protein levels of COX-2 were analyzed by RT-PCR and Western blotting, respectively. RESULTS: LPS increased the mRNA expression of COX-2 and production of PGE₂ in a dose and time dependent manners in HBECs. Induction of COX-2 mRNA and protein by LPS were inhibited by lipoxin A₄ in a dose-dependent manner. Lipoxin A₄ also significantly decreased LPS-induced production of PGE₂. CONCLUSION: Lipoxin A₄ down-regulates LPS-induced expression of COX-2 and consequently inhibits the production of PGE₂ in HBECs.     

Release of arachidonic acid metabolites fromblood by cultivation of human amniotic fluid with oneself blood

AIM: To investigate the effect of human amniotic fluid on the release of thromboxane A₂ (TXA₂), prostaglandin I₂ (PGI₂) and Leukotriene C₄ (LTC₄) from blood cells. METHODS: 1 mL human amnioticfluid and 10 mL oneself blood collected from 38-41 weeks with cesarean section were cultured at 37 ℃ for 30 min, and then centrifuged. The supernatants were taken and stored at -70 ℃. TXB₂ and 6-Keto-PGF_1α of the superntants were determined by radioimmunoassay and LTC₄ by enzyme immunoassay. RESULTS: It was found that the levels of TXB₂ and LTC₄ in blood were elevated from (63.5±52.0)ng/L and (40.1±39.2) ng/L to (189.1±102.0) ng/L and (293.5±206.1) ng/L, respectively (P<0.01), after cultivation of oneself amniotic fluid with blood, the concentrations of TXB₂ and LTC₄ were higher in meconium-stained group than those in clear amniotic fluid group, but the concentration of PGI₂ only elevated slightly from (27.4±11.6) ng/L to (33.9±10.6) ng/L (P>0.05). CONCLUSION: Amniotic fluid might stimulate the release of TXA₂ and LTC₄ from blood, it might affect the balance of TXA₂ and PGI₂ in blood, which might play an important role in the pathogenesis of amniotic fluid embolism.     

Effect of crystallin βB2 on the aging of lens

AIM: To study the effect of crystallin βB₂ on the aging of lens. METHODS: SD rats were maintained routinely and killed at 6 different ages (1 d, 8 d, 2 weeks, 8 weeks, 8 months and 1.5 years). Water-soluble crystallins were extracted and separated by two-dimensional polyacrylamide gel electrophoresis (IEF/SDS-PAGE). After Comassize blue staining, the crystallin patterns were screened and analyzed. βB₂ crystallin and the main chaperone proteins (αA₂, αB₂) were identified and the relative quantity was measured. RESULTS: (1) The quantity of water-soluble crystalline βB₂ increased in close relation to the aging of the rat. (2) αA₂, αB₂ chaperone proteins increased with the aging of the rat too. (3) The change of the quantity of water-soluble crystalline βB₂ was closely related to the changes of αA₂ , αB₂ chaperone proteins. (4) Degraded and modified crystallins began to appear clearly in the lens after 8 months old. CONCLUSION: Based on our results, we infer that water-soluble crystalline βB₂ increases with the aging dof the rat, which is helpful to maintain the structure and transparency of the lens.     

Effects of drynaria total flavonoids on serum levels of leptin,interleukin 6, prostaglandin E2 and expression of bone β2-adrenergic receptor in ovariectomized osteoporosis rats

AIM: To investigate the effects of drynaria total flavonoids on serum levels of leptin (LEP), interleukin 6(IL-6), prostaglandin E₂(PGE₂) and the expression of bone β₂-adrenergic receptor (ADRB2) in a rat model of ovariectomized osteoporosis(OP). METHODS: The osteoporosis model was established by ovariectomy. Twelve weeks after modeling,bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry to verify successful modeling.Enzyme-linked immunosorbent assay was applied to detect the concentrations of LEP, IL-6 and PGE₂ in serum. The expression of ADRB2 was determined by immunohistochemical technique. RESULTS: Compared with sham group,BMD of the rats in model group significantly decreased in multiple regions 12 weeks after modeling(P<0.01). The serum levels of LEP, IL-6 and PGE₂ in model group were significantly higher than those in sham group(P<0.05). The levels of LEP, IL-6 and PGE₂ in drynaria total flavonoids group were significantly lower than those in model group(P<0.01). No significant difference of PGE₂ between these 2 groups was observed. The ADRB2 expression in sham group and treatment group was significantly different from that in model group, and no significant difference between sham group and treatment group was found. CONCLUSION: The serum levels of LEP, IL-6 and PGE₂ and the expression of bone ADRB2 increased in OP rats.Drynaria total flavonoids reduce the production of LEP, IL-6 and the expression of ADRB2, and suppress the bone absorption, which may be one of the mechanisms in treating OP.     

Role of central PGE2 on sympathetic excitation in chronic heart failure

AIM: To observe the effect of central prostaglandin E₂ (PGE₂) on sympathetic activation in chronic heart failure (CHF) and to explore the underlying mechanism. METHODS: Male SD rats were subjected to coronary artery ligation to induce heart failure (HF), and the intracerebroventricular infusion was performed by osmotic pump continuously. The rats in sham group and HF group were given artificial cerebrospinal fluid (0.25 μL/h). The rats in HF plus treatment group was given celecoxib (CLB; 20 mg/h). After 4 weeks, the levels of PGE₂ in cerebrospinal fluid (CSF), the sympathetic nerve excitability and cardiac function were measured, and the changes of corticotropin-hormone releasing hormone (CRH)-containing neurons activation and neurotransmitter contents in the hypothalamic paraventricular nucleus (PVN) were also determined. RESULTS: Compared with the sham-operated rats, the HF rats had raised level of PGE₂ in CSF, up-regulated renal sympathetic nerve activity and plasma norepinephrine, increased left ventricular end diastolic pressure, lung-to-body weight and right ventricular-to-body weight ratios, and decreased maximal increase and decreased rate of left ventricular pressure (P<0.05). In addition, the number of CRH positive neurons in PVN and the level of plasma adrenocorticotropic hormone were higher in HF rats than those in sham-operated rats (P<0.05). After administration of CLB into the lateral ventricle of HF rats, the contents of PGE₂ in CSF were significantly reduced, the number of activation CRH neurons in PVN was decreased, the excitability of sympathetic nerves was down-regulated and cardiac function was improved (P<0.05). Compared with the sham-operated rats, the content of glutamic acid in PVN of HF rats was increased, the content of γ-aminobutyric acid and the number of glutamate decarboxylase 67-positive neurons were decreased (P<0.05). After the CLB was given, the above indexes were reversed (P<0.05). CONCLUSION: These findings indicate that in CHF, the increased central PGE₂ may activate CRH-containing PVN neurons and contribute to the augmented sympathetic drive possibly by modulating the neurotransmitters within the PVN.     

Role of α1 adrenoceptor in proliferation of hypoxic pulmonary artery smooth muscle cells

AIM: To investigate the role of α₁ and β₂ adrenoceptors(α₁AR and β₂AR) in the proliferation of hypoxic pulmonary artery smooth muscle cells (PASMCs).METHODS: PASMCs were isolated by an explant method from neonatal bovine pulmonary arteries. The cultured PASMCs were exposed to 6.6% O₂ for 6 h, 12 h and 24 h. The method of -TdR incorporation was used to measure the proliferation of PASMCs. _i was assayed with Fura-2/AM. The mRNA expression of α₁AR, β₂AR, c-fos and c-myc was determined by Northern blotting. The effects of activation of α₁AR and β₂AR, and inhibition of α₁AR on the above indexes were observed by treating PASMCs with different AR agonists and antagonists under hypoxic condition.RESULTS: Significant increase in TdR incorporation in hypoxic PASMCs with α₁AR activation was observed, and marked decrease in that was induced by α₁AR inhibition. However, no significant change was found after β₂AR activation. _i , the mRNA expression of c-fos, c-myc, α₁AR and β₂AR in PASMCs were increased after hypoxia.CONCLUSION: Hypoxia induces the increase in _i and mRNA expression of c-fos and c-myc, leading to the proliferation of PASMCs. The hypoxic proliferation of PASMCs is intervened by α₁AR, but not β₂AR. The remodeling of pulmonary arteriole and pulmonary hypertension may be involved in the processes of pulmonary arteriole constriction and proliferation induced by hypoxia through up-regulation of α₁AR.     

EP2A promotes human CD34+ cell homing in vitro but not proliferation

AIM: To investigate the role of prostaglandin E₂ receptor 2 agonist (EP₂A) in proliferation and homing of human CD34⁺ cells. METHODS: Bone marrow fluid and peripheral blood containing stem cells were collected from healthy donors mobilized by granulocyte colony-stimulating factor in our department. Human CD34⁺ cells were isolated by the method of magnetic-activated cell sorting microbeads. Bone marrow mononuclear cells were isolated by Ficoll-Paque centrifugation, and the bone marrow mesenchymal stem cells (BMMSC) were cultured with L-DMEM. Human CD34⁺ cells and BMMSC were divided into 4 groups, and treated with PGE₂ (as positive control), DMSO (as negative control), EP₂A and EP₂A+prostaglandin E₂ receptor 2 antagonist (EP₂AA), respectively. After exposed to the reagents, human CD34⁺ cell viability was measured by CCK-8 assay, the number of colonies was evaluated by colony-formation assay, the cell cycle distribution was analyzed by flow cytometry, and the protein expression of survivin, β-catenin and CXC chemokine receptor 4 (CXCR4) was detrmined by Western blot. Moreover, the concentration of stromal cell-derived factor-1α (SDF-1α) in the BMMSC was detected by ELISA. RESULTS: The cell viability and the colony number of human CD34⁺ cells in EP₂A group were not higher than those in negative control group. Furthermore, the proportion of human CD34⁺ cells treated with EP₂A in G₂/M phase was not elevated compared with negative control group. The protein expression of survivin and β-catenin did not up-regulated in human CD34⁺ cells exposed to EP₂A, but the protein expression of CXCR4 in human CD34⁺ cells and the concentration of SDF-1α in BMMSC were elevated. CONCLUSION: EP₂A promotes human CD34⁺ cell homing in vitro but not proliferation.     

Role of Rho kinase in diabetic vascular endothelial dysfunction

AIM: To investigate the role of Rho kinase in diabetic vascular endothelial dysfunction. METHODS: SD rats, genetic db/db diabetic model and high-fat diet-induced obese mice were used in this study. The thoracic aorta of the rats or mice were isolated and suspended in organ bath or myograph for measurement of the changes in isometric tensions. The levels of phosphorylated endothelial nitric oxide synthase(eNOS) were determined by Western blotting. Thromboxane B₂(TXB₂),prostaglandin F_2α(PGF_2α) and thromboxane receptor (TP receptor) activators in artery were measured by ELISA. RESULTS: Endothelium-dependent vasorelaxation was attenuated by TP receptor activation, which was ameliorated by Rho kinase inhibitors. The improved endothelium-dependent vasorelaxation by inhibition of Rho kinase was abolished by pretreatment with the inhibitor of eNOS. Consistently, the level of phosphorylated eNOS was inhibited by TP receptor activation, which was reversed by inhibition of Rho kinase. The endothelium-dependent vasorelaxation was also improved by Rho kinase inhibitors in diabetic and obese animals. The levels of TXB₂ and PGF_2α in the arteries were increased in diabetic animals compared with the controls. CONCLUSION: Rho kinase plays a role in diabetic endothelial dysfunction, which may be related to TP receptor activation and eNOS inhibition.     

Expression of cyclooxygenase-2 in IL-1β-stimulated mesangial cells is medicated by NF-κB/IκB signal pathway

AIM: To investigate the role of NF-κB/IκB signal pathway in the regulation of cyclooxygenase-2 (COX-2) expression in human mesangial cells (HMC). METHODS: The PGE₂ concentration in supernatants of HMC was measured by radioimmunoassay. COX-2 mRNA and protein expression were determined by RT-PCR and Western blot. Electrophoretic mobility shift assay (EMSA) and Western blot were used to detect the activity of NF-κB and degradation of IκB. RESULTS: IL-1β significantly upregulated COX-2 expression and PGE₂ production in HMC. Significant up-regulation of NF-κB activation, nuclear translocation of p65 subunit, and degradation of IκB α and IκB β were observed in IL-1β-induced HMC. CONCLUSION: Expression of COX-2 in IL-1β-induced HMC is mediated by NF-κB/IκB signal pathway.     

Prostaglandin E2 receptors,EP2 and EP4, regulate expression of surface molecules and cytokines in B-cells of collagen-induced arthritic mice

AIM: To observe the immunoregulatory effects of prostaglandin E₂ receptor (EP) subtypes EP2/EP4 on the B-cells of collagen-induced arthritic(CIA)mice. METHODS: DBA/1 mice were immunized with chicken type II collagen emulsified in Freunds complete adjuvant to induce arthritis. B-cells were isolated from the splenocyte suspension by positive selection using anti-CD19 monoclonal antibody immunomagnetic beads. The expression of MHC II, CD 80 and CD86 was examined by flow cytometry. The mRNA levels of EPs, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), IL-6, IL-4, IL-10 and transforming growth factor-β (TGF-β) were detected by real-time RT-PCR. RESULTS: The rank of the mRNA levels of EPs was EP2>EP1>EP3>EP4 in B-cells and EP2/EP4 mRNA expression was obviously increased in CIA mice. EP2 antagonists inhibited the expression of MHC II, CD80 and CD86. EP4 antagonist had little effect on CD80. EP2/EP4 antagonists inhibited the mRNA expression of IFN-γ, TNF-α, and IL-6 (P<0.05 or P<0.01) and increased the expression of IL-10 (P<0.01 or P<0.05). Furthermore, the antagonists of EP2 and EP4 also increased the mRNA expression of IL-4 and TGF-β (P<0.01), respectively. CONCLUSION: PGE₂ modulate the pathogenesis of CIA via EP2/EP4 by regulating the expression of surface molecules and cytokines in B-cells. EP2/EP4 may be a new therapeutic target for treating rheumatoid arthritis.     

Acute pulmonary injury caused by echinococcus granulosus cyst fluid

AIM:to establish an animals model of pulmonary embolism caused by echinococcus granulosus (E.g)cyst fluid.METHODS:Cyst fluid were isolated from sheep liver . Twenty-one rabbits were randomized into 3 groups: group Ⅰ(saline group), group Ⅱ(clear cyst fluid group), group Ⅲ (sand-contained cyst fluid group). Operation was performed on each animal to place a femoral artery catheter and a femoral vein catheter. Saline, clear cyst fluid or sand-contained cyst fluid were given to rabbits at a dose of 3 mL/kg body weigh . Observations were then made at 10, 30, 60 minutes to determine the changes of MAP, blood gas and vaso-active substance. Then ECT scanning image was obtained .After observation, all animals were killed and the lungs were harvested for histological examination by light microscopy.RESULTS:Remarkable decline of PaO₂, MAP and rise of TXB₂, 6-keto-PGF_1α were observed in group Ⅲ and group Ⅱ(P＜0.05). ECT examination showed radioactivity defect in group Ⅲ and radioactivity weakening of the lung in group Ⅱ. Histological examination of the lungs showed that sand-contained cyst fluid may cause an "ARDS-like" change.CONCLUSION:Animals in group Ⅲ basically simulated the clinical situation of pulmonary embolism caused by E.g cyst content. The sand contained in the fluid played an important role in damaging the lung. Vaso-active substance had relevance to the lung injury.     

Effects of thymosin α1 on the development and maturation of thymocytes

AIM: To investigate the effect of Thymosin α₁ on the development and matutation of thymocytes. METHODS: The proportion of CD4⁺CD8⁺ thymocytes and the expression of smoothened (Smo) of the hedgehog (Hh)-signaling in CD4^-CD8^-thymocytes were examined to observe the effect of thymosin α₁ on thymocyte development and matutation. RESULTS: Flowcytometric analysis showed that thymosin α₁ showed activity at a low dose of 30 μg/kg, and 30 μg/kg thymosin α₁ accelerated the replenishment and maturation of thymocytes according to the expression of Smo of the Hh-signaling in CD4^-CD8^-thymocytes, the potent negative regulator of proliferative responses. CONCLUSION: Thymosin α₁ can accelerates thymocyte development from CD4^-CD8^- to CD4⁺CD8⁺.     

Localization and expression of TGF-β1,2 in fetal and adult skins

AIM:To explore the localization and expression of transforming growth factor-β_1,2 (TGF-β_1,2) and alpha-smooth muscle actin (α-ASMA) in fetal and adult skins. METHODS:Skins of 15 cases of fetuses with different gestational ages and 5 cases of adults were taken, embedded with paraffin wax, and sectioned. Immunohistochemistry method and pathological method were used to detect the expression intensity and distribution of TGF-β_1,2 and α-ASMA. RESULTS: Positive immunohistochemical signals of TGF-β_{1, 2} and α-ASMA were found in fetal and adult skins. In skins derived from young fetus, the positive signals of these three proteins were very weak. Along with the increment in gestational age, the positive cellular rates of TGF-β_1,2M and α-ASMA were elevated progressively. In elder fetal and adult skins, TGF-β_1,2 were mostly distributed in epidermal cells, endothelial cells and some fibroblasts, while α-ASMA was mainly located in myofibroblasts and sweat gland epithelial cells. CONCLUSION:The endogenous TGF-β_1,2might be involved in the cutaneous development at embryonic stage, in the cutaneous structure maintenance at adult stage, and in the wound healing after injury.     

Effects of several harmful factors on expression of glycine receptor α1 subunit in neonatal rat myocardial cells

AIM: To study the expression of glycine receptor α₁ subunit in neonatal rat myocardial cells and to investigate the effect of lipopolysaccharide (LPS), hypoxia/reoxygenation, isoproterenol (ISO) and high concentration of glucose (HG) on the expression of glycine receptor α₁ subunit in the neonatal rat myocardial cells. METHODS: Neonatal rat myocardial cells were cultured in vitro. The expression of glycine receptor α₁ subunit was detected by Western blotting. The neonatal rat myocardial cells were treated with LPS (20 mg/L), ISO (100μmol/L) or high concentration of glucose (25 mmol/L) for 24 h, or were exposed to hypoxia for 3 h followed by reoxygenation for 3 h. Subsequently, the cell viability was measured by CCK-8 assay, and the expression of glycine receptor α₁ subunit was determined by Western blotting. RESULTS: The expression of glycine receptor α₁ subunit in the neonatal rat myocardial cells was positively detectable by Western blotting. Compared with control group, no significant difference of the cell viability (P>0.05) in LPS group, ISO group, hypoxia/reoxygenation group and HG group was observed. The expression of glycine receptor α₁ subunit was increased (P<0.01) in LPS group, ISO group and hypoxia/reoxygenatio group, but decreased (P<0.01) in HG group. CONCLUSION: Glycine receptor α₁ subunit exists in the neonatal rat myocardial cells. A certain concentration of LPS or ISO, or hypoxia/reoxygenation for a certain period upregulate the expression of glycine receptor α₁ subunit, but HG downregulates the expression of glycine receptor α₁ subunit in cultured neonatal rat myocardial cells.     

Effects of schisandrin B on apoptosis of lens epithelial cells treated with H2O2

AIM: To investigate the effects of Schisandrin B (Sch B) on apoptosis of lens epithelial cells (LEC) treated with H₂O₂. METHODS: Eyes in SDrats were excised and lenses were separated under operating microscope in sterilized condition. Lenses were divided randomly into four groups with different treatment: control group, hydrogen peroxide group (H₂O₂), pirenoxine sodium group (PS) and schisandrin Bgroup (Sch B). Lenses were incubated in CO₂ incubator for 24 h with 300 μmol·L^-1 H₂O₂ and with or without 0.5 mmol·L^-1 Sch B. LECaoptosis and apoptosis rate were measured by TUNELmethod. Ultrastructure changes and apoptosis bodies of LECwere observed via transmitted electron microscope. RESULTS: (1) Apoptosis rate in H₂O₂ group (92.0±2.6) was significantly higher than that in control group (3.5±1.8). Apoptosis rate in Sch Bgroup (13.8±3.27) was remarkably lower than that in H₂O₂ group and PSgroup. (2) Ultrastructure observation indicated that apoptosis cells occurred in most LEC in H₂O₂ group and the changes were severe presenting different stages. While a few apoptosis cells were observed in Sch Bgroup, the changes were slight and most of them were in early and middle stages. CONCLUSION: These data indicated that Sch Bsignificantly inhibited apoptosis of LECduring experimental oxidative injury, the effects were stronger than PS.     

USP14 regulates H2O2 induced oxidative stress in H9c2 cells

AIM:To evaluate the effect of inhibiting ubiquitin-specific protease 14(USPl4) activity on oxidative stress induced by H₂O₂ of H9c2 cells.METHODS:The H9c2 cells were incubated with H₂O₂ at 25 μmol/L for 2 h to establish the oxidative stress injury model.The cells were divided into control group,H₂O₂ group,IU1 group (25 μmol/L or 50 μmol/L) and IU1+H₂O₂ group.The H9c2 cells activity was measured by MTS assay.The level of intracellular reactive oxygen species (ROS) and cell survival rate were analyzed by flow cytometry assay.The changes of the mitogen-activated protein kinase (MAPK) family related proteins were detected by Western blot.RESULTS:Compared with control group,the cell activity and the viability rate in H₂O₂ group were decreased (P<0.05),while the intracellular ROS,the protein levels of Bax/Bcl-2,P53,p-ERK1/2,p-JNK and p-P38 were increased (P<0.05).Compared with H₂O₂ group,the cell activity and the viability rate of the H9c2 cells in IU1+H₂O₂ group were increased (P<0.05),while the intracellular ROS,the protein levels of Bax/Bcl-2,P53,p-ERK1/2,p-JNK and p-P38 were decreased (P<0.05).CONCLUSION:Inhibition of USPl4 activity reduces the oxidative stress injury of the H9c2 cells.The mechanism may be related to inhibition of the MAPK signaling and down-regulation of apoptosis related proteins.