摘要目的 评价二氮嗪预先给药对大鼠心肌微血管内皮细胞缺氧复氧时磷脂酰肌醇-3激酶(PI3K) mRNA和蛋白质丝氨酸苏氨酸激酶(Akt) mRNA表达的影响.方法 培养SD大鼠心肌微血管内皮细胞,以1×106个/ml密度接种于96孔培养板(100μl/孔)或培养皿(2 ml/皿),采用随机数字表法,将其随机分为4组(n=25).正常对照组(C组)不作任何处理；缺氧复氧组(H/R组)、二氮嗪预先给药组(DZ组)、二氮嗪预先给药+线粒体ATP敏感性钾通道阻断剂5-羟葵酸组(DZ+ 5-HD组)均进行缺氧2h,复氧2h.DZ组和DZ+ 5-HD组在缺氧前2h分别加入100 μmol/L二氮嗪、100μnol/L二氮嗪+ 100 μmol/L 5-羟葵酸.于复氧2h时测定细胞活力、细胞凋亡率、PI3K mRNA和Akt mRNA表达.结果 与C组比较,H/R组细胞活力降低,细胞凋亡率升高,PI3K mRNA和Akt mRNA表达上调(P＜0.05或0.01)；与H/R组比较,DZ组细胞活力升高,细胞凋亡率降低,PI3K mRNA和Akt mRNA表达上调(P ＜0.05或0.01)；5-羟葵酸可逆转二氮嗪预先给药导致的上述改变(P＜0.05或0.01).结论 二氮嗪预先给药减轻大鼠心肌微血管内皮细胞缺氧复氧损伤的机制与激活线粒体ATP敏感性钾通道,促进PI3K和Akt基因的转录有关.

abstractsObjective To investigate the effects of diazoxide pretreatment on expression of phosphatidylinositol 3-kinase(PI3K) mRNA and protein serine/threonine kinase(Akt) mRNA in rat myocardial microvascular endothelial cells exposed to hypoxia-reoxygenation (H/R).Methods The SD rat myocardial microvascular endothelial cells were cultured.The cells were seeded in 96-well plates ( 100μd/hole) or in 6 cm diameter dishes (2 ml/dish) with the density of 1 × 106/ml and randomly divided into 4 groups ( n =25 each):normal control group (group C),H/R group,diazoxide pretreatment group (group DZ) and diazoxide pretreatment + 5-hydroxydecanoate (5-HD,a mitochondrial ATP-sensitive potassium channel blocker) group (group DZ + 5-HD).The cells were exposed to 2 h hypoxia followed by 2 h reoxygenation.Diazoxide 100 μmol/L and diazoxide 100 μmol/L + 5-HD 100 μmol/L were added to the culture medium 2 h before hypoxia in groups DZ and DZ + 5-HD respectively.The cell viability,apoptotic rate and expression of PI3K mRNA and Akt mRNA were detected at the end of reoxygenation.Results Compared with group C,the cell viability was significantly decreased,while the apoptotic rate increased and expression of PI3K mRNA and Akt mRNA up-regulated in group H/R (P ＜0.05 or 0.01).Compared with group H/R,the cell viability was significantly increased,while the apoptotic rate decreased and expression of PI3K mRNA and Akt mRNA up-regulated in group DZ (P ＜ 0.05 or 0.01).5-HD could inhibit diazoxide pretreatment-induced changes mentioned above (P ＜ 0.05 or 0.01 ).Conclusion Diazoxide pretreatment can reduce H/R injury by promoting PI3K gene and Akt gene transcription through activation of mitochondrial ATP-sensitive potassium channels in rat myocardial microvascular endothelial cells.