JNK通路促进大鼠脑缺血再灌注海马神经元凋亡

JNK pathway promotes apoptosis of rat hippocampal neurons after cerebral ischemia and reperfusion

目的:探讨c-Jun N端激酶(JNK)通路在大鼠脑缺血再灌注后海马神经元凋亡中的作用。方法:雄性SD大鼠90只,随机分为假手术组、全脑缺血再灌注组、全脑缺血再灌注+JNK抑制剂(SP600125)组、全脑缺血再灌注+JNK激动剂(茴香霉素)组和全脑缺血再灌注+溶剂对照组,每组再灌注后24 h取材。分别采用免疫组化、Western blotting和实时荧光定量PCR检测海马神经元caspase-3蛋白和mRNA的表达;采用TUNEL染色检测海马神经元凋亡情况。结果:全脑缺血再灌注组caspase-3蛋白和mRNA表达较假手术组增加(P<0.05);与全脑缺血再灌注组相比,全脑缺血再灌注+JNK抑制剂组caspase-3蛋白和mRNA表达均降低(P<0.05),而全脑缺血再灌注+JNK激动剂组caspase-3蛋白和mRNA表达均增加(P<0.05),全脑缺血再灌注+溶剂对照组则无明显变化(P>0.05)。各组海马神经元凋亡趋势与caspase-3蛋白和mRNA变化趋势一致。结论:JNK通路的激活可增加大鼠脑缺血再灌注后海马神经元caspase-3的表达,促进海马神经元凋亡。

To investigate the effect of c - Jun N - terminal kinase （JNK） pathway on the apoptosis of hippoeampal neurons after cerebral ischemia - reperfusion （IR） in SD rats. METHODS： Ninety rats were randomly divid- ed into 5 groups： sham group, cerebral IR group, cerebral IR ＋ JNK inhibitor （SP600125） group, cerebral IR ＋ JNK agonist （anisomyein） group and cerebral IR ＋ vehicle group. The brain samples were collected 24 h after reperfusion. The protein level of caspase -3 in hippocampal neurons was measured by immunohistoehemical and Western blotting techniques. The mRNA expression of caspase - 3 in the hippocampus was determined by real - time fluorescence quantitative PCR. The ap- optosis of hippocampal neurons was detected by TUNEL staining. RESULTS ： Compared with sham group, the expression of caspase - 3 at mRNA and protein levels in cerebral IR group increased obviously （ P 〈 0.05 ）. Compared with cerebral IR group, the expression of caspase -3 at mRNA and protein levels in cerebral IR ＋ JNK inhibitor group decreased obvi- ously （P 〈 0. 05 ）, and those in cerebral group increased obviously （ P 〈 0. 05 ）. However, the expression of caspase - 3 at mRNA and protein levels in cerebral IR ＋ vehicle group had no obvious change （P 〉 0.05）. The apoptosis of hippocampal neurons in each group was consistent with the changes of caspase - 3 at mRNA and protein levels. CONCLUSION： Acti- vation of JNK pathway enhances caspase - 3 expression in rat hippocampal neurons after cerebral IR, thus promoting the ap- optosis of the neurons.