【作者】 徐佳骏；

【导师】 孙学军； 彭兆云； 李润平； 徐伟刚； 陶恒沂；

【作者基本信息】 第二军医大学 ， 航空、航天和航海医学， 2007， 硕士

【摘要】 乙酰唑胺是防治急性高原病(Acute Mountain Sickness,AMS)的首选药物,其机制主要是通过引起机体代谢性酸中毒,增加化学感受器对高原低氧的敏感性。低氧诱导因子-1(hypoxia-inducible factor-1, HIF-1)是机体低氧耐受的核心转录因子,其基因产物在血管形成重塑、葡萄糖和能量代谢、细胞增值等方面发挥重要作用。我们应用Western Blot法、real-time PCR、DNA结合ELISA、报告基因法分别检测了乙酰唑胺给药后(100 mg/kg或50 mg/kg,IP,5 d)大鼠脑组织内和常氧酸性环境处理后(pH6.5,20 h)大鼠原代皮层神经元和PC12细胞内HIF-1蛋白含量及活性的变化。我们发现乙酰唑胺可诱导大鼠脑皮层和海马组织内HIF-1α蛋白及其DNA结合活性的增加,同时其下游基因促红细胞生成素(EPO),血管内皮生长因子(VEGF)、葡萄糖转运蛋白-1(GLUT-1)的mRNA表达增加。常氧酸性环境可使原代皮层神经元和PC12细胞HIF-1α蛋白含量增加,同时HIF-1调控报告基因表达上调。我们推测乙酰唑胺可能通过酸中毒诱导脑内HIF-1使机体产生低氧耐受,预防低氧性损伤,参与乙酰唑胺防治AMS的机制。更多还原

【Abstract】 Acetazolamide, a potent carbonic anhydrase inhibitor, has had a long history of effectiveness in prevention and treatment of acute mountain sickness (AMS). Traditionally, acetazolamide’s efficacy has been attributed to metabolic acidosis, which is allowance of chemoreceptors to respond more fully to hypoxic stimuli at altitude. Hypoxia inducible factor (HIF) controls the transcription of genes involved in angiogenesis, erythropoiesis, glycolysis, and cell survival. HIF-1αlevels are a critical determinant of HIF activity. HIF-1αprotein level and HIF-1 DNA binding activities were increased in cerebral cortices and hippocampus of rats dosed with acetazolamide (100 mg/kg or 50 mg/kg, IP) for 5 days. Moreover, the mRNA levels of erythropoietin (Epo), glucose transporter-1 (Glut-1), vascular endothelial growth factor (Vegf), which are regulated by HIF-1, also increased. The normoxic induction of HIF-1αand HIF-1 mediated genes by acetazolamide might participate the mechanisms in which acetazolamide reduces symptoms of AMS. In further studies, cultured cortical neurons obtained from embryonic day 18 rats and PC12 cells were exposed to AP (pH 6.5) or SD (pH 7.2) media for 20 h under normoxia. The HIF-1αprotein level and activity of HIF-driven chloramphenicol acetyltransferase (CAT) reporters of cortical neurons and PC12 cells treated with acidosis media were significantly enhanced. The normoxic induction of HIF-1 activity by acidosis might play an important role in induction of the critical hypoxic regulatory factor HIF-1 by acetazolamide.更多还原