JNK通路在内质网应激预处理诱导脑缺血耐受中的作用

Effect of the JNK pathway in the brain ischemic tolerance induced by endoplasmic reticulum stress preconditioning

目的探讨JNK通路在内质网应激预处理诱导海马CA1区神经元缺血耐受中的作用及其机制。方法将144只SD大鼠随机分为假手术(SH)组、缺血/再灌注(I/R)组、内质网应激预处理(IP)组、IP+IR组、Curcu-min+I/R(CU)组、Curcumin+IP+I/R(CP)组、Anisomycin+IR(AN)组、Anisomycin+IP+I/R(AP)组及溶剂对照+I/R(VE)组。采用TUNEL法检测海马CA1区凋亡细胞,免疫组化法和Western-Blot法检测GRP78、p-JNK及c-Jun蛋白在海马CA1区的表达。结果 SH组GRP78蛋白表达微弱,与其相比,I/R、CU、AN及VE组表达升高(P<0.05),IP、IP+IR、CP、AP组表达明显升高(P<0.01);与IP组比较,IP+IR、CP、AP组GRP78蛋白表达升高(P<0.05);与I/R组比较,IP+I/R、CU及CP组海马CA1区凋亡锥体细胞数和p-JNK及c-Jun蛋白表达水平均降低(P均<0.01),降低程度为CP组>IP组>CU组,AN组CA1区凋亡锥体细胞数和p-JNK、c-jun蛋白表达水平升高(P均<0.01);Anisomycin可部分抵消内质网应激预处理的保护效应。结论 JNK通路参与大鼠海马CA1区神经元缺血性凋亡,内质网应激预处理可通过抑制CA1区JNK磷酸化、减少c-Jun蛋白表达而保护海马细胞,内质网应激预处理与抑制JNK通路激活对脑缺血耐受有相似的保护作用。

Objective To investigate the effect and the mechanism of the JNK pathway in hippocampal CA1 area ischemic tolerance induced by endoplasmic reticulum stress preconditioning. Methods 216 SD rats were randomly divided into sham （SH） group, isehemia/reperfusion （I/R） group, endoplasmic retieulum stress precon ditloning （IP） group, IP ＋ I/R group（ IP ＋ I/R）, Cureumin ＋ I/R（CU） group, Cureumin ＋ IP ＋ I/R（CP） group, Anisomycin ＋ ]JR group（ AN）, Anisomycin ＋ IP ＋ I/R （AP） group and solvent control ＋ I/R（VE） group. In hippocampal CA1 area, using TUNEL to test apoptosis, using immunohistochemistry and Western-Blot to find the difference of GRP78, p-JNK and c-jun. Results SH had a little GRP78 protein. Compared with SH, I/R, CU, AN and VE increased （ P 〈 0.05） ; IP, IP ＋ IR, CP, AP increased significantly （P 〈 0.01 ）. Compared with the IP, IP ＋ IR, CP, AP increased （all P 〈 0.05 ）. Compared with I/ R, IP ＋I/R, CU and CP reduced the number of apoptosis cells and p-JNK and c-Jun （ all P 〈 0.01 ）. The effect of that was CP 〉 IP 〉 CU; AN increased the number of apoptosis cells and enhanced p-JNK and c-Jun （ P 〈 0.01 ） ; AP offsetted the protection of IP partially. Conclusions The activation of JNK pathway is involved in ischemic neuronal apoptosis in hippocampal CA1 area. Endoplasmic retieulum stress preconditioning may inhibit JNK phosphorylated and reduce c-Jun to protect hippocampal CA1 area neurons. To inhibit the activation of JNK pathway may play a similar protective effect of endoplasmic reticulum stress.