PI3K-Akt信号转导通路在舒芬太尼后处理减轻大鼠心肌缺血再灌注损伤中的作用

目的探讨磷脂酰肌醇-3-激酶/丝氨酸-苏氨酸激酶(PI3K-Akt)信号转导通路在舒芬太尼后处理减轻大鼠心肌缺血再灌注损伤中的作用。方法健康雄性SD大鼠50只,体质量230²80 g,2280 g,2³月龄,采用随机数字表法,将其随机分为5组(n=10):假手术组(S组)、心肌缺血再灌注损伤组(I/R组)、舒芬太尼后处理组(PO组)、舒芬太尼后处理组+PI3K特异性抑制剂LY294002组(PO+L组)、PI3K特异性抑制剂LY294002组(L组)。I/R组,PO组,PO+L组,L组采用结扎左冠状动脉前降支30 min,再灌注120 min的方法来建造心肌缺血再灌注的模型。I/R组在再灌注前5 min时尾静脉注射0.9%氯化钠注射液1 ml,PO组在再灌注前5 min时尾静脉注射1ml舒芬太尼稀释液1μg/kg,PO+L组尾静脉注射1 ml舒芬太尼稀释液1μg/kg+LY2940020抑制剂0.3mg/kg,L组尾静脉注射1 ml LY2940020抑制剂0.3 mg/kg。于再灌注120 min时处死大鼠,取缺血部位心肌组织,用10%甲醛固定,常规石蜡包埋,切片。光镜下观察病理学结果,采用免疫组织化学方法测定心肌细胞Akt及磷酸化Akt(p-Akt)的表达,计算p-Akt平均吸光度值与Akt平均吸光度值的比值(p-Akt/Akt),采用TUNEL染色法检测心肌细胞凋亡,计算心肌细胞凋亡指数(AI)。结果与S组比较,其余4组AI、p-Akt/Akt的表达均升高(P<0.05);PO组比I/R组、PO+L组、L组AI降低,p-Akt/Akt的表达升高(P<0.05);PO+L组比L组AI降低,p-Akt/Akt的表达升高(P<0.05);I/R组与PO+L组及L组上述指标比较差异无统计学意义(P>0.05)。结论 PI3K-Akt信号转导通路参与了舒芬太尼后处理减轻大鼠心肌缺血再灌注损伤的作用。

Effects of PI3K-Akt signaling pathway on sufentanil postconditioning-mediated alleviation of myocardial ischemia-reperfusion injury in rats

Objective To investigate the roles of phosphatidylinositol 3-kinase （PI3K）/protein-serine-threonine kinases （Akt） signaling pathway on sufentanil postconditioning-mediated alleviation of myocardial ischemia-reperfusion （I/R） injury in rats. Methods Fifty healthy male SD rats weighed 230-280g 2-3 months of age were randomly allocat- ed to Sham operation group （group S, n=10）, group I/R （n=10）, sufentanil postconditioning group （group PO, n=10）, sufentanil postconditioning＋LY294002 （a specific PI3K inhibitor） group （group PO＋L, n=10） and LY294002 group （group L, n=10）. In groups I/R, PO＋L and L, the I/R model was constructed by occlusion of anterior descending branch of the left coronary artery for 30 rain followed by reperfusion for 120 rain. In groups I/R, PO, PO＋L and L rats were treated with 1 ml normal saline, 1μg/kg sufentanil, llxg/kg sufentanil plus 0.3mg/kg LY294002 and 0.3mg/kg LY294002 intravenous infusion via the sublingual vein for 5 min prior to reperfusion, respectively. The rats were sac- rificed at 120 min of reperfusion and the ischemic myocardial tissues were extracted for post-fixation with formalin and embedded with paraffin followed by sections. This entailed microscopic examination and determination of the expres- sion of Akt, phosphorylated Akt （p-Akt） via immunohistochemistry assay. The ratio of p-Akt/Akt was calculated ac- cordingly. Myocardial apoptosis was detected by TUNEL for calculation of the apoptotic index. Results Compared with group S, the AI and the ratio of p-Akt/Akt were increased in miscellaneous groups （all P〈0.05）. Compared with group PO, AI was significantly higher and the ratio of p-Akt/Akt lower in groups I/R, PO＋L and L （all/）〈0.05）. AI was lower and the ratio of p-Akt/Akt higher in group PO＋L compared with that in group L （both P〈0.05）. There was no sig- nificant difference in the aforementioned parameters between group I/R and group PO＋L or L （all P〉0.05）. Conclusion PI3K-Akt signaling pathway is involved in the sufentanil postconditioning-mediated myocardial I/R injury in rats.