JNK通路促进大鼠脑缺血再灌注海马神经元凋亡

目的:探讨c-JunN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24h取材。分别采用免疫组化、Westernblotting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。

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

AIM:To investigate the effect of c-Jun N-terminal kinase(JNK) pathway on the apoptosis of hippocampal neurons after cerebral ischemia-reperfusion(IR) in SD rats.METHODS: Ninety rats were randomly divided into 5 groups: sham group,cerebral IR group,cerebral IR+JNK inhibitor(SP600125) group,cerebral IR+JNK agonist(anisomycin) 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 immunohistochemical and Western blotting techniques.The mRNA expression of caspase-3 in the hippocampus was determined by real-time fluorescence quantitative PCR.The apoptosis 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 obviously(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: Activation of JNK pathway enhances caspase-3 expression in rat hippocampal neurons after cerebral IR,thus promoting the apoptosis of the neurons.