Objective: Highland natives adapt well to the hypoxic environment at high altitude(HA). Several genes have been reported to be linked to HA adaptation. Previous studies showed that the endothelial nitric oxide synthas...Objective: Highland natives adapt well to the hypoxic environment at high altitude(HA). Several genes have been reported to be linked to HA adaptation. Previous studies showed that the endothelial nitric oxide synthase(ENOS) G894 T polymorphism contributed to the physiology and pathophysiology of humans at HA by regulating the production of NO. In this meta-analysis, we evaluate the association between the ENOS G894 T polymorphism and HA adaptation through analyzing the published data. Methods: We searched all relevant literature about the ENOS G894 T polymorphism and HA adaptation in Pub Med, Medline, and Embase before Step 2015. A random-effects model was applied(Revman 5.0), and study quality was assessed in duplicate. Six studies with 634 HA native cases and 621 low-altitude controls were included in this meta-analysis. Results: From the results, we observed that the wild-type allele G was significantly overrepresented in the HA groups(OR=1.85; 95% CI, 1.47–2.33; P<0.0001). In addition, the GG genotype was significantly associated with HA adaptation(OR=1.99; 95% CI, 1.54–2.57; P<0.0001). Conclusion: Our results showed that in 894 G allele carriers, the GG genotype might be a beneficial factor for HA adaptation through enhancing the level of NO. However, more studies were needed to confirm our findings due to the limited sample size.展开更多
Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopte...Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopterin （BH4）. Treatment of human EA.hy 926 endothelial cells with dexamethasone decreased mRNA and protein expression of both BH4-synthesizing enzymes： GTP cyclobydrolase I and dihydrofolate reductase. Consistently, a concentration- and time-dependent reduction of BH4, dihydrobiopterin （BH2） as well as BH4：BH2 ratio was observed in dexamethasone-treated cells. Surprisingly, no evidence for eNOS uncoupling was found. We then analyzed the expression and phosphorylation of the eNOS enzyme. Dexamethasone treatment led to a down-regulation of eNOS protein and a reduction of eNOS phosphorylation at serine 1177. A reduction of eNOS expression may lead to a relatively normal BH4： eNOS molar ratio in dexamethasone-treated cells. Because the BH4-eNOS stoichiometry rather than the absolute BH4 amount is the key determinant of eNOS functionality （i.e., coupled or uncoupled）, the down-regulation of eNOS may represent an explanation for the absence of eNOS uncoupling. Phosphorylation of eNOS at serine 1177 is needed for both the NO-producing activity of the coupled eNOS and the superoxide-producing activity of the uncoupled eNOS. Thus, a reduction of serine 1177 phosphorylation may render a potentially uncoupled eNOS hardly detectable. Conclusions Although dexamethasone reduces BH4 levels in endothelial cells, eNOS uncoupling is not evident. The reduction of NO production in dexamethasone-treated endothelial cells is mainly attributable to reduced eNOS expression and decreased eNOS phosphorylation at serine 1177.展开更多
【目的】探讨黄芪甲苷对糖尿病肾病大鼠的治疗作用及机制。【方法】将27只大鼠随机分为正常组、模型组、黄芪甲苷组,每组9只。模型组、黄芪甲苷组大鼠给予高脂饲料喂养联合链脲佐菌素(STZ)40 mg/kg腹腔注射构建2型糖尿病肾病模型。造模...【目的】探讨黄芪甲苷对糖尿病肾病大鼠的治疗作用及机制。【方法】将27只大鼠随机分为正常组、模型组、黄芪甲苷组,每组9只。模型组、黄芪甲苷组大鼠给予高脂饲料喂养联合链脲佐菌素(STZ)40 mg/kg腹腔注射构建2型糖尿病肾病模型。造模成功后,黄芪甲苷组给予黄芪甲苷40 mg/kg灌胃治疗,正常组、模型组给予等体积生理盐水,每日1次,持续12周。12周后,测定大鼠空腹血糖(FBG)、尿白蛋白/尿肌酐比值(UACR)、血尿素氮(BUN)、血清肌酐(SCr)水平;苏木素-伊红(HE)染色法观察肾脏病理结构变化;过碘酸雪夫(PAS)染色、马松(Masson)染色法观察肾脏纤维化程度;定量聚合酶链反应(qPCR)、蛋白免疫印迹(Western Blot)法检测肾脏组织中腺苷酸蛋白活化激酶(AMPK)、内皮型一氧化氮合酶(e NOS)mRNA及蛋白表达水平。【结果】与模型组比较,黄芪甲苷组大鼠FBG、UACR显著降低(P<0.05),BUN、SCr含量未见明显改变;与模型组比较,黄芪甲苷组大鼠肾小球体积减小,基底膜增厚、系膜基质增生、肾小囊腔狭窄程度、胶原纤维沉积明显减轻;进一步的实验结果显示,黄芪甲苷组肾脏组织中AMPK、e NOS m RNA表达水平较模型组明显升高(P<0.05),AMPK的磷酸化水平及eNOS蛋白表达水平较模型组明显上调(P<0.05)。【结论】黄芪甲苷可改善大鼠糖尿病肾损害,其机制可能与激活AMPK/eNOS信号通路有关。展开更多
目的通过门静脉部分结扎建立门静脉高压症大鼠模型,检测大鼠肠系膜动脉内皮一氧化氮合酶(e NOS)、热休克蛋白90(Hsp90)的表达,探讨二者在门静脉高压大鼠内脏高动力循环中的作用。方法检测假手术组(SHAM组)和门静脉高压症组(PHG组)大鼠...目的通过门静脉部分结扎建立门静脉高压症大鼠模型,检测大鼠肠系膜动脉内皮一氧化氮合酶(e NOS)、热休克蛋白90(Hsp90)的表达,探讨二者在门静脉高压大鼠内脏高动力循环中的作用。方法检测假手术组(SHAM组)和门静脉高压症组(PHG组)大鼠肠系膜动脉中e NOS、Hs P90的表达。结果 e NOS、Hs P90在门静脉高压症组(PHG组)的表达比假手术组(SHAM组)显著升高。结论 e NOS和Hsp90S在门静脉高压症高动力循环中发挥重要作用。展开更多
基金supported by the National Natural Science Foundation of China(81372125)
文摘Objective: Highland natives adapt well to the hypoxic environment at high altitude(HA). Several genes have been reported to be linked to HA adaptation. Previous studies showed that the endothelial nitric oxide synthase(ENOS) G894 T polymorphism contributed to the physiology and pathophysiology of humans at HA by regulating the production of NO. In this meta-analysis, we evaluate the association between the ENOS G894 T polymorphism and HA adaptation through analyzing the published data. Methods: We searched all relevant literature about the ENOS G894 T polymorphism and HA adaptation in Pub Med, Medline, and Embase before Step 2015. A random-effects model was applied(Revman 5.0), and study quality was assessed in duplicate. Six studies with 634 HA native cases and 621 low-altitude controls were included in this meta-analysis. Results: From the results, we observed that the wild-type allele G was significantly overrepresented in the HA groups(OR=1.85; 95% CI, 1.47–2.33; P<0.0001). In addition, the GG genotype was significantly associated with HA adaptation(OR=1.99; 95% CI, 1.54–2.57; P<0.0001). Conclusion: Our results showed that in 894 G allele carriers, the GG genotype might be a beneficial factor for HA adaptation through enhancing the level of NO. However, more studies were needed to confirm our findings due to the limited sample size.
文摘Objective To find out whether dexamethasone induces an uncoupling of the endothelial nitric oxide synthase （eNOS）. Methods ＆ Results A major cause of eNOS uncoupling is a deficiency of its cofactor tetrahydrobiopterin （BH4）. Treatment of human EA.hy 926 endothelial cells with dexamethasone decreased mRNA and protein expression of both BH4-synthesizing enzymes： GTP cyclobydrolase I and dihydrofolate reductase. Consistently, a concentration- and time-dependent reduction of BH4, dihydrobiopterin （BH2） as well as BH4：BH2 ratio was observed in dexamethasone-treated cells. Surprisingly, no evidence for eNOS uncoupling was found. We then analyzed the expression and phosphorylation of the eNOS enzyme. Dexamethasone treatment led to a down-regulation of eNOS protein and a reduction of eNOS phosphorylation at serine 1177. A reduction of eNOS expression may lead to a relatively normal BH4： eNOS molar ratio in dexamethasone-treated cells. Because the BH4-eNOS stoichiometry rather than the absolute BH4 amount is the key determinant of eNOS functionality （i.e., coupled or uncoupled）, the down-regulation of eNOS may represent an explanation for the absence of eNOS uncoupling. Phosphorylation of eNOS at serine 1177 is needed for both the NO-producing activity of the coupled eNOS and the superoxide-producing activity of the uncoupled eNOS. Thus, a reduction of serine 1177 phosphorylation may render a potentially uncoupled eNOS hardly detectable. Conclusions Although dexamethasone reduces BH4 levels in endothelial cells, eNOS uncoupling is not evident. The reduction of NO production in dexamethasone-treated endothelial cells is mainly attributable to reduced eNOS expression and decreased eNOS phosphorylation at serine 1177.
文摘【目的】探讨黄芪甲苷对糖尿病肾病大鼠的治疗作用及机制。【方法】将27只大鼠随机分为正常组、模型组、黄芪甲苷组,每组9只。模型组、黄芪甲苷组大鼠给予高脂饲料喂养联合链脲佐菌素(STZ)40 mg/kg腹腔注射构建2型糖尿病肾病模型。造模成功后,黄芪甲苷组给予黄芪甲苷40 mg/kg灌胃治疗,正常组、模型组给予等体积生理盐水,每日1次,持续12周。12周后,测定大鼠空腹血糖(FBG)、尿白蛋白/尿肌酐比值(UACR)、血尿素氮(BUN)、血清肌酐(SCr)水平;苏木素-伊红(HE)染色法观察肾脏病理结构变化;过碘酸雪夫(PAS)染色、马松(Masson)染色法观察肾脏纤维化程度;定量聚合酶链反应(qPCR)、蛋白免疫印迹(Western Blot)法检测肾脏组织中腺苷酸蛋白活化激酶(AMPK)、内皮型一氧化氮合酶(e NOS)mRNA及蛋白表达水平。【结果】与模型组比较,黄芪甲苷组大鼠FBG、UACR显著降低(P<0.05),BUN、SCr含量未见明显改变;与模型组比较,黄芪甲苷组大鼠肾小球体积减小,基底膜增厚、系膜基质增生、肾小囊腔狭窄程度、胶原纤维沉积明显减轻;进一步的实验结果显示,黄芪甲苷组肾脏组织中AMPK、e NOS m RNA表达水平较模型组明显升高(P<0.05),AMPK的磷酸化水平及eNOS蛋白表达水平较模型组明显上调(P<0.05)。【结论】黄芪甲苷可改善大鼠糖尿病肾损害,其机制可能与激活AMPK/eNOS信号通路有关。
文摘目的通过门静脉部分结扎建立门静脉高压症大鼠模型,检测大鼠肠系膜动脉内皮一氧化氮合酶(e NOS)、热休克蛋白90(Hsp90)的表达,探讨二者在门静脉高压大鼠内脏高动力循环中的作用。方法检测假手术组(SHAM组)和门静脉高压症组(PHG组)大鼠肠系膜动脉中e NOS、Hs P90的表达。结果 e NOS、Hs P90在门静脉高压症组(PHG组)的表达比假手术组(SHAM组)显著升高。结论 e NOS和Hsp90S在门静脉高压症高动力循环中发挥重要作用。
