藏红花素预处理减轻大鼠胃缺血再灌注损伤作用与PI3K/Akt信号通路的关系

Protective effect against gastric ischemia/reperfusion injuries induced by crocin preconditioning and its relationship with PI3K/Akt signaling pathway in rats

目的探讨藏红花素预处理对大鼠胃缺血再灌注(GI?R)损伤的保护作用及其与PI3K/Akt信号通路的关系。方法采用分离并夹闭大鼠腹腔动脉30 min,去除动脉夹恢复血流1 h的方法制备GI?R模型。健康雄性SD大鼠30只,采用随机数字表法分为5组,每组6只:假手术组(Sham组)、胃缺血再灌注组(GI?R组)、溶剂对照组(Vehicle组)、藏红花素预处理组(crocin组)、藏红花素预处理联合PI3K/Akt信号通路抑制剂LY294002组(crocin+LY组)。记录各组大鼠胃黏膜损伤指数,并采用TUNEL法和免疫组化方法检测胃黏膜上皮细胞凋亡和增殖情况。测算大鼠胃黏膜组织中丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性。蛋白质印迹法(Western Blot)法检测胃黏膜组织Bcl?2,Bax,p?Akt蛋白的表达。结果成功制备大鼠GI?R损伤模型。与GI?R组相比,crocin组大鼠胃黏膜损伤指数、胃黏膜细胞凋亡率降低;胃黏膜组织MDA含量降低,SOD活性增强;p?Akt的蛋白表达水平增强,且Bcl?2蛋白表达增强,Bax蛋白表达减弱(P<0.05)。而LY294002可减弱crocin的以上作用(P<0.05)。结论crocin对抗大鼠胃缺血再灌注损伤的保护作用机制可能与其上调PI3K/Akt信号通路活性,上调Bcl?2蛋白表达,下调Bax蛋白表达等作用有关。

Objective To investigate the protective effect of preconditioning with crocin against gastric ischemia?reperfusion(GI?R)injury in rats and the role of PI3K/Akt signaling pathway.Methods GI?R injury rat model was established by clamping of the celiac artery for 30 min and reperfusion for 1 hour.Male SD rats were randomly divided into five groups(n=6):Sham group,GI?R group,Vehicle group,crocin group,and crocin+LY294002 group.At the end of reperfusion,the gastric mucosal injury index was re?corded.TUNEL and immunohistochemical methods were employed to asses the gastric mucosal cell apoptosis and proliferation.The malondialdehyde(MDA)concentration,superoxide dismutase(SOD)activity we?re determined by colorimetric assays.Subsequently,the expression of Bcl?2,Bax and p?Akt was examined by western blotting.Results The gastric is?chemia?reperfusion injury rat model was successfully established.The results showed that crocin preconditioning remarkably reduced the gastric mucosal in?jury index,the gastric mucosal cell apoptotic rate and the contents of malon?dialdehyde(MDA),and enhanced the activities of superox?ide dismutase(SOD)as compared with GI?R group.Crocin pretreatment apparently restrained gastric mu?cosal cells apoptosis as evi?denced by decreasing the level of Bax expression,incresing the level of phosphorylation of Akt and Bcl?2 expression(P<0.05).These effects were reversed by LY294002,a blocker of PI3K/Akt signaling path?way.Conclusion The protection of crocin precon?ditioning against GI?R may be related to enhancing the activity of PI3K/Akt signaling pathway,upregulating the expression of Bcl?2 protein and downregulating the expression of Bax protein.