目的 研究七氟醚后处理对大鼠心肌缺血再灌注损伤的保护作用是否与血红素氧合酶-1(HO-1)表达上调有关,且这种表达上调机制与激活磷脂酰肌醇-3-激酶/丝氨酸-苏氨酸激酶(PI3K-Akt)信号通路的关系.方法 取健康雄性SD大鼠30只,体质量230~290 g,按随机数字表法分为5组(每组6只):假手术组(S组)、心肌缺血再灌注损伤组(I/R组)、七氟醚后处理组(Se组)、七氟醚后处理+PI3K抑制剂渥漫青霉素(Wort-man-nin)组(Se+W组)、Wortmannin组(W组).S组:丝线穿过冠状动脉左前降支(LAD)但不结扎;其余4组均进行结扎和再灌注过程,I/R组:结扎LAD 30 min再灌注120 min;Se组:在恢复血供前1 min吸入1.0 MAC的七氟醚5 min;Se+W组:操作同七氟醚后处理组,但在给予七氟醚前,经股静脉注入PI3K抑制剂Wortmannin(15μg/kg);W组:在恢复血供前5 min经股静脉注射Wortmannin(15μg/kg).再灌注120 min时,①采腹主动脉血测肌钙蛋白(cTn-I)含量.②取大鼠心尖组织测定丙二醛(MDA)含量及超氧化物歧化酶(SOD)活力.③蛋白质印迹法测待测心尖组织中Akt、p-Akt及HO-1蛋白的表达,并计算p-Akt Akt比值.结果 与S组比较,其余4组cTn-I、p-Akt Akt、HO-1及MDA含量明显升高,SOD活力降低,差异有统计学意义(P<0.05);与I/R组相比,Se组cTn-I、MDA含量下降明显,p-Akt Akt比值、HO-1蛋白表达、SOD活力升高,差异有统计学意义(P<0.05);与Se组比较,Se+W组及W组血清cTnI含量、心肌组织MDA含量显著升高,心肌组织HO-1、p-Akt表达下调,p-Akt Akt降低,心肌组织SOD活力降低,差异有统计学意义(P<0.05).结论 七氟醚后处理通过影响HO-1表达对大鼠的心肌缺血再灌注损伤产生保护作用,其机制可能与PI3K-Akt通路介导有关.%Objective To investigate whether the protective effect of sevoflurane postconditioning on myocar-dial ischemia-reperfusion injury in rats is related to the up-regulation of heme oxygenase-1 (HO-1) expression, and to determine the relationship between the up-regulation mechanism and the activation of phosphatidylinositol-3-kinase/serine-threonine kinase (PI3K-Akt) signaling pathway. Methods Thirty healthy male SD rats weighing 230-290 g were randomly divided into 5 groups (n=6 each): the sham operation group (group S), myocardial ischemia/reperfusion injury group (group I/R), sevoflurane postconditioning group (group Se), Se+PI3K inhibitor Wortmannin group (group Se+W), and group W. Group S: the thread passed through the left anterior descending coronary artery (LAD) without ligation. The other four groups underwent ligation and reperfusion. Group I/R: 30 min LAD ligation followed by 120 min reperfusion. Group Se: received 1.0 minimum alveolar concentration (MAC) of sevoflurane for 5 min at the 1 min before recovery of blood supply. Group Se+W: injected with PI3K inhibitor Wortmannin (15 μg/kg) before the rats were given sevoflurane and the procedure was the same as that in the Se group. Group W:Wortmannin (15 μg/kg) was injected through femoral vein at 5 min before the recovery of blood supply. At 120 min after reperfusion: ① the con-tent of cardiactroponin I (cTn-I) in the abdominal aortic blood was tested; ② The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in the myocardial tissues of rats were measured; ③ The expression of Akt, p-Akt and HO-1 protein in the myocardial tissues was measured by Western blotting, and the ratio of p-Akt/Akt was calculated. Results Compared with group S, the contents of cTn-I, p-Akt/Akt, HO-1 and MDA in the other four groups significantly increased, the activity of SOD decreased, and the differences were statistically significant ( P<0.05). Compared with group I/R, the contents of cTn-I and MDA in Se group significantly decreased, the p-Akt/Akt ratio, HO-1 protein expression and SOD activity increased, and the differences were statistically significant ( P<0.05). Compared with group Se, the contents of serum cTnI and MDA in myocardium significantly increased in the Se+W group and W group, the expression of HO-1 and p-Akt in myocardium was down-regulated, the p-Akt/Akt and SOD activity in myocardium decreased, and there were statistically significant differences ( P<0.05). Conclusion Sevoflu-rane postconditioning shows protective effect on myocardial ischemia-reperfusion injury in rats by affecting the expres-sion of HO-1, and its mechanism may be related to the mediation of PI3K-Akt pathway.
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