PI3K/Akt通路在缺血后处理减轻小鼠肠缺血再灌注损伤中的作用

Role of PI3K/Akt Signal Pathway in the Protective Effect of Ischemia Postcondition on Intestinal Ischemia-Reperfusion-Induced Intestinal Injury

目的:探讨磷脂酰肌醇3-激酶(PI3K)/丝氨酸-苏氨酸蛋白激酶(Akt)信号通路在肠缺血后处理减轻小鼠肠缺血再灌注损伤中的作用。方法:将30只健康雄性C57BL/6J小鼠随机分为3组:假手术组(S组)、缺血再灌注组(IR组)、缺血后处理+缺血再灌注组(IPO组)。采用无创动脉夹夹闭肠系膜上动脉根部45min恢复灌注2h的方法制备小鼠肠缺血再灌注损伤模型,IPO组于再灌注前给予3个循环的灌注30s,缺血30s的处理。2h后处死小鼠,留取小肠组织,观察组织病理改变行chiu’s病理学损伤评分。测定血清D-乳酸水平、肠脂肪酸结合蛋白(I-FABP)浓度、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性;检测小肠组织含水量以及PI3K、Akt、p-Akt蛋白的表达情况。结果:与S组比较,IR组血清D-乳酸水平、I-FABP浓度、MDA含量增高,SOD活性降低,肠组织含水量、PI3K及p-Akt蛋白表达上调,Chiu’s病理学损伤评分显著增高(P<0.05);与IR组相比,IPO组血清D-乳酸及IFABP浓度降低,MDA含量下降,SOD活性显著增高,肠组织PI3K及p-Akt蛋白表达降低,Chiu’s病理学损伤评分降低(P<0.05)。结论:缺血后处理减轻小鼠肠缺血再灌注损伤的机制可能与激活PI3K/Akt信号通路有关。

Objective： To investigate the effect of phosphatidylinositol 3-kinase（PI3K）/protein-serine- threonine kinases（Akt） signal pathway in ischemia postconditioning （IPO）-induced alleviation of intestinal ischemia-reperfusion （IR） injury in mice. Methods： Thirty healthy male C57BL/6J mice were randomly divided into 3 groups： Sham operation group （group S）, group IR, and group IPO. The model of intestinal IR was established by occlusion of superior mesenteric artery for 45 min followed by 2 h reperfusion. The mice of IPO group underwent 3 cycles of 30 s reperfusion and 30 s ischemia before 2 h reperfusion. The mice were sacrificed after 2 h of reperfusion and the small intestines were removed. The pathological changes of the intestinal mucosal were observed and evaluated by Chiu＇s score. The concentrations of serum D-lactate and intestinal fatty acid binding protein （I-FABP）, malondialdehyde （MDA） content and superoxide dismutase （SOD） activation in each group were detected. The intestinal wet/dry weight ratios, the expression of PI3K, Akt, phospho-Akt were examined in intestinal tissues. Results. Compared with group S, there was a significant increase of the intestinal wet/dry weight ratios, Chiu＇s score, the level of serum D-lactate, I-FABP, and MDA content, SOD activity decreased, PI3K and phospho-Akt protein expression were upregulated in group IR （P〈0.05）. Compared with group IR, there was a significant decrease of the intestinal wet/dry weight ratios, Chiu＇s score, the level of serum D- lactate, I-FABP, and MDA content, and an increase of SOD activity and PI3K, while a down- regulation of phospho-Akt protein expression in group IPO （P〈0.05）. Conclusion. The postcon- ditioning-induced protection is partly mediated by antioxidant activities via activation of the PI3K/ Akt pathway.