CpG-ODN对大鼠脑缺血/再灌注损伤的保护作用

Effect of OCpG-ODN on cerebral tissues injured by cerebral ischemia/reperfusion and JAK and STAT expressions in rats

目的探讨CpG-ODN对大鼠脑缺血/再灌注(I/R)损伤的保护作用及其机制。方法将54只大鼠随机分为假手术组、脑I/R模型组、CpG-ODN组,每组18只。采用大脑中动脉线栓法构建大鼠脑I/R模型。CpG-ODN组造模前1 h腹腔注射CpG-ODN(10μg/25 g),脑I/R模型组注射等量生理盐水。再灌注12 h采用Longa 5分评分法评估神经功能。再灌注24 h采用TTC染色测定脑梗死体积,HE染色观察组织结构,TUNEL染色分析细胞凋亡,PCR检测酪氨酸激酶(JAK)、信号转导和转录激活因子(STAT)m RNA表达水平,免疫印迹法分析Caspase3、Caspase7、JAK、p-JAK、STAT和p-STAT蛋白水平。结果与假手术组比较,脑I/R模型组神经功能障碍严重,脑梗死体积显著增大,脑组织发生水肿、坏死等病变;与脑I/R模型组比较,CpG-ODN组明显改善。与假手术组比较,脑I/R模型组脑组织细胞凋亡率和Caspase3、Caspase7蛋白水平明显升高(P<0.05),脑I/R模型组JAK、STAT mRNA水平和蛋白磷酸化程度显著上调(P<0.05);与脑I/R模型组比较,CpG-ODN组细胞凋亡率和Caspase3、Caspase7蛋白水平明显降低(P<0.05),JAK、STAT mRNA和蛋白磷酸化程度均明显下降(P<0.05)。结论 CpG-ODN能有效保护大鼠脑I/R损伤,其机制可能与影响JAK、STAT蛋白磷酸化抑制细胞凋亡有关。

Objective To explore protective effect of oCpG-ODN on cerebral tissues injured by cerebral ischemia/reperfusion(I/R)and the expressions of Janus kinase(JAK)and signal transduction and activator of transcription(STAT)in rats.Methods Brain I/R model was constructed by middle cerebral artery occlusion(MCAO)method.Fifty-four SD rats were randomly divided into three groups of 18 animals each,i.e.sham operation group,brain I/R group,and CpG-oligodeoxynucleotide(CpG-ODN)treatment group,in which 10μg/25g CpG-ODN was intraperitonealy injected before the MCAO.Neurological function,cerebral infarction volume and morphological changes in the cerebral tissues were determined.The cells apoptosis and JAK and STAT mRNA levels and JAK,phosphorylated JAK,p-JAK,STAT,p-STAT and Caspase 3 and 7 proteins expressions in the infarct cerebral tissues were detected 24 hours after I/R.Results The cerebral dysfunction was significantly more severe and the volumes of the cerebral infarction was significantly bigger in the I/R group than those in CpG-ODN treatment group(P<0.05),which were significantly more severe and bigger than those in the sham operation group(P<0.05).The cell apoptosis rate,Caspase 3 and 7 proteins levels,the expression levels of mRNA of STA and JAK,and the levels of p-STA and p-JAK protein expressions were significantly higher in I/R group than those in the sham operation group and CpG-ODN treatment group.The levels of p-STA and p-JAK proteins expressions were significantly higher in CpG-ODN treatment group than those in the sham operation group(P<0.05).Conclusion It is suggested that CpG-ODN can effectively protect injured cerebral tissues after I/R possibly by promoting JAK and STAT protein phosphorylation and inhabiting cell apoptosis.