JNK通路在缺血预处理诱导海马神经元保护中的作用

Role of c-jun N-terminal kinase cascade on neuronal protection with ischemic preconditioning in hippocampus in gerbil

目的探讨JNK通路在缺血预处理诱导海马神经元保护中的作用。方法♂蒙古沙土鼠,随机分为假手术组(SH)、缺血/再灌注组(I/R)、缺血预处理组(IP)、Anisomy-cin组(AN)、Curcumin组(CU)、Anisomycin复合IP组(AP)、Curcumin复合IP组(CP)及溶剂对照组(VE),每组据再灌注15min、2、4、6h、1、3、5及7d又分8个亚组。预定时间点行TUNEL海马CA1区凋亡细胞检测、免疫组化SP法检测p-JNK及Jun蛋白在海马CA1区的表达变化。结果IP、CU及CP可减少海马CA1区凋亡锥体细胞数(vsI/R,P<0.01),减弱CA1区再灌注各点p-JNK及Jun蛋白的表达水平(vsIR,P<0.01),该效应CP组>IP组>CU组。AN增加CA1区凋亡锥体细胞数(vsIR,P<0.01),增强CA1区再灌后1d内各点p-JNK及再灌后1～7d各点Jun蛋白表达水平(vsIR,P<0.01)。AP部分抵消IP保护效应。结论JNK通路激活参与沙土鼠海马CA1区缺血性神经元凋亡,缺血预处理可通过抑制CA1区JNK磷酸化、减少Jun蛋白表达而保护海马细胞和功能。抑制JNK通路激活可发挥缺血预处理相似的保护作用。

Aim To investigate the role of c-jun N-terminal kinase cascade on neuronal protection with ischemic preconditioning in hippocampus in gerbil. Methods Forebrain ischemia was induced by occlusion of bilateral carotid arteries and confirmed by isoelectricity of EEG. Male gerbils were randomly divided into sham group （ SH ）, ischemic-reperfusion group （ IR ）, ischemic preconditioning group （IP）, specific agonist of JNK-Anisomycin group （ AN ） , specific antagonist of JNK-Curcumin group （ CU ）, Anisomycin combined with IP（AP） group, Curcumin combined with IP（CP） group and solvent control group （VE）. The gerbils were killed in 15min, 2, 4, 6 h, 1, 3, 5 and 7 d in each group following reperfusion. The number of apoptosis neurons in hippocampal CA1 region were counted. The activities of p-JNK and c-Jun expression in hippocampal CA1 region were detected using SP immunohistochemical technique. Results The number of apoptosis neurons were significant less and the levels of p-JNK or Jun expression were markedly decreased in hippocampal CA1 region in each point in group IP, CUand CP than that in group IR（P 〈0. 01 ）. This effect was less in group IP than in group CP, but was more than in group CU. Anisomycin could increase the number of apoptosis neurons （vs IR, P 〈 0. 01 ） and the levels of p-JNK expression at 15 min, 2, 4, 6 h or Jun expression at 1,3, 5 and 7 d （ vs IR, P 〈 0. 01 ） after reperfusion. Anisomycin combined with IP could partly counteract neuroprotective effects of IP. Conclusion Activation of JNK cascade in hippocampal CA1 region may participate in neuroal ischemic injury and apoptosis. Ischemic preconditioning display neuroprotective effects by inhibiting the expression of JNK and Jun in hippocampal CA1 region. Inhibition JNK cascade may educe the resemble neuroprotective effects of IP.