Apelin受体在缺血性脑卒中大鼠皮质及海马的表达变化

Expression of Apelin receptor in cortex and hippocampus of ischemic stroke rats

目的 探讨Apelin受体(APJ)在缺血性脑卒中大鼠皮质及海马的表达变化。方法 选择雄性8周龄SD大鼠30只,随机分为假手术组和脑卒中组,每组15只。采用大脑中动脉闭塞法获得大鼠缺血性脑卒中模型,缺血2 h再灌注24 h后利用Zea Longa法和TTC染色法评价大鼠神经功能、测定脑梗死体积;利用苏木精-伊红染色检测大鼠大脑皮质及海马区存活神经元形态及数目;利用免疫组织化学法和Western blot技术检测大鼠大脑皮质及海马区B淋巴细胞瘤2基因(Bcl-2)、Bax和APJ蛋白表达,利用RT-PCR检测APJ mRNA表达。结果 脑卒中组大鼠神经行为学评分明显高于假手术组[(2.58±0.51)分vs 0分,P<0.01]。TTC染色显示,脑卒中组大鼠脑梗死体积明显高于假手术组[(32±1)%vs 0,P<0.01]。苏木精-伊红染色显示,与假手术组比较,脑卒中组大鼠大脑皮质及海马神经元数目明显减少[(234.00±22.87)个vs(290.70±26.50)个,P<0.05;(79.33±3.79)个vs(99.67±6.43)个,P<0.01]。Western blot和RT-PCR结果显示,与假手术组比较,脑卒中组大鼠大脑皮质及海马Bax、APJ蛋白和mRNA表达明显升高,Bcl-2表达明显降低,差异有统计学意义(P<0.05,P<0.01)。结论 脑卒中大鼠缺血侧皮质和海马区均出现苍白色梗死灶,并且神经细胞凋亡,可能与APJ高表达有关。

Objective To investigate the expression of Apelin receptor(APJ) in the cortex and hippocampus of ischemic stroke rats.Methods Thirty male SD rats aged 8 weeks were randomly divided into sham operation group and stroke group, with 15 rats in each group.The ischemic stroke model was established by middle cerebral artery occlusion followed by 2 h of ischemia and 24 h of reperfusion.Zea Longa method and TTC staining were used to evaluate the neurological function and determine the cerebral infarct volume.HE staining was applied to observe the morphology and number of survival neurons in the cerebral cortex and hippocampus.The expression of B lymphoblastoma 2(Bcl-2),Bax, and APJ in the cerebral cortex and hippocampus was detected by Western blotting and immunohistochemical assay, and the mRNA level of APJ was tested with RT-PCR.Results The neurobehavioral score was significantly higher in the stroke group than the sham operation group(2.58±0.51 vs 0,P<0.01).TTC staining showed that the infarct volume was obviously larger in the stroke than the sham operation group [(32±1)% vs 0,P<0.01].HE staining displayed that there were less number of neurons in the cerebral cortex and hippocampus in the stroke group than the sham operation group(234.00±22.87 vs 290.70±26.50,P<0.05;79.33±3.79 vs 99.67±6.43,P<0.01).Western blotting and RT-PCR results showed that the protein and mRNA levels of APJ and Bax in the cerebral cortex and hippocampus were notably higher, while those of Bcl-2 were decreased in the stroke group than the sham operation group(P<0.05,P<0.01).Conclusion Pale infarcts are found in the ischemic cortex and hippocampus of stroke rats, so are apoptotic neuronal cells, which may be related to the high expression of APJ.