特异性抑制JAK2/STAT3信号通路对大鼠急性脑缺血再灌注损伤后COX-2和VEGF表达水平的影响

目的 探讨特异性抑制蛋白酪氨酸激酶2/信号转导与激活子3(JAK2/STAT3)信号通路对急性脑缺血再灌注损伤大鼠脑组织环氧合酶-2(COX-2)和血管内皮生长因子(VEGF)表达水平的影响。方法 采用线栓法制备大鼠急性大脑中动脉闭塞再灌注模型; 大鼠随机分为假手术组、模型组和给药组; 给药组大鼠于再灌注前5 min腹腔注射JAK2/STAT3信号通路抑制剂AG490(1 mg/kg),其余2组给予等量生理盐水; 再灌注24 h后各组行神经功能缺损评分,用氯化三苯基四氮唑(TTC)染色法检测大鼠脑梗死体积,用实时荧光定量PCR(RT-qPCR)检测脑组织中JAK2、STAT3、环氧合酶2(COX-2)和血管内皮生长因子(VEGF)的mRNA相对表达水平,用蛋白印迹(Western blot)检测脑组织磷酸化JAK2(p-JAK2)、磷酸化STAT3(p-STAT3)、COX-2和VEGF的蛋白相对表达水平。结果 与假手术组比较,模型组大鼠神经功能缺损评分、脑梗死体积、JAK2和STAT3的mRNA,p-JAK2和p-STAT3蛋白、COX-2的mRNA和蛋白相对表达水平均显著升高(P<0.05),VEGF的mRNA和蛋白相对表达水平显著降低(P<0.05); 与模型组比较,给药组大鼠神经功能缺损评分、脑梗死体积、JAK2和STAT3的mRNA、p-JAK2和p-STAT3蛋白、COX-2的mRNA和蛋白相对表达水平均显著降低(P<0.05),VEGF的mRNA和蛋白相对表达水平显著升高(P<0.05)。结论 特异性抑制JAK2/STAT3信号通路可能通过降低脑组织中COX-2表达和促进VEGF表达来保护大鼠急性脑缺血再灌注损伤。

The effects of specific inhibition of JAK2/STAT3 signaling pathway on the expression levels of COX-2 and VEGF in rats with acute cerebral ischemia reperfusion injury

ObjectiveTo investigate the effects of specific inhibition of JAK2/STAT3 signaling pathway on the expression levels of COX-2 and VEGF in rats with acute cerebral ischemia reperfusion injury.Methods The acute middle cerebral artery occlusion reperfusion model was prepared by the suture method in rats. The rats were randomly divided into the sham operation group, the model group and the drug administration group. The rats in the drug administration group were injected intraperitoneally with JAK2/STAT3 signaling pathway inhibitor AG490(1 mg/kg)5 min before reperfusion, and the other two groups were given the same amount of normal saline. Twenty-four hours after reperfusion, the neurological deficit score were performed in each group. The volume of cerebral infarction in rats was measured by triphenyl tetrazolium chloride(TTC)staining. RT-qPCR was used to detect mRNA expression levels of JAK2, STAT3, COX-2 and VEGF in brain tissues, and Western blot was used to detect protein expression levels of p-JAK2, p-STAT3, COX-2 and VEGF.Results Compared with the sham operation group, the neurological score, cerebral infarction volume, mRNA expression levels of JAK2 and STAT3, protein expression levels of p-JAK2 and p-STAT3 protein, and mRNA and protein expression levels of COX-2 in the model group were significantly increased(P<0.05), and mRNA and protein expression levels of VEGF were significantly reduced(P<0.05). Compared with the model group, the neurological score, cerebral infarction volume, mRNA expression levels of JAK2 and STAT3, protein expression levels of p-JAK2 and p-STAT3, and mRNA and protein expression levels of COX-2 in the administration group were significantly reduced(P<0.05), and mRNA and protein expression levels of VEGF were significantly increased(P<0.05).Conclusion Specific inhibition of JAK2/STAT3 signaling pathway might protect brain injury in rats with acute cerebral ischemia reperfusion injury by reducing COX-2 expression and promoting VEGF expression in brain tissue.