脑缺血预处理对脑缺血再灌注大鼠的保护作用及对神经营养因子表达的影响

Neuroprotective Effects of Cerebral Ischemic Preconditioning

目的:观察脑缺血预处理(CIP)对再次缺血损伤大鼠的保护作用及脑组织中神经营养因子脑源性神经营养因子(BDNF),胶质细胞源性神经营养因子(GDNF)及血管内皮生长因子(VEGF)蛋白表达的变化,探讨脑缺血耐受的作用机制。方法:Wistar大鼠随机分为3组,分别为假手术组(Sham),脑缺血再灌注损伤组(I/R),脑缺血预处理再次损伤组(CIP+MCAO)。采用神经缺损评分(NDS)法评价行为学的改变,苏木素-伊红(HE)染色法评价脑组织病理形态的改变、酶联免疫吸附法(ELISA)检测血清中神经元特异性烯醇化酶(NSE)的水平,免疫组化法观察BDNF,GDNF,VEGF在皮质、海马CA1区的表达变化。结果:与Sham组比较,I/R组大鼠神经缺损评分明显升高,脑组织病理损伤程度较明显,血清中NSE水平明显升高(P<0.01),大鼠患侧脑组织皮层、海马CA1区BDNF阳性表达面积和积分吸光度IA均明显降低,但仅有脑组织皮层与Sham组比较有统计学差异(P<0.01);与I/R组比较,CIP+MCAO组可明显降低大鼠的神经缺损评分(P<0.05),明显减轻脑组织病理损伤程度(P<0.05),降低血清中NSE水平(P<0.01),CIP+MCAO组大鼠患侧脑组织皮层、海马CA1区BDNF,VEGF阳性表达面积和IA均明显增加(P<0.05,P<0.01)。GDNF的阳性表达虽有增加的趋势但没有统计学差别。结论:脑缺血预处理的神经保护作用与上调BDNF,VEGF内源性保护蛋白的表达有关。

Objective： To observe the neuroprotective effects of cerebral ischemic preconditioning（ CIP） on cerebral ischemia reperfusion and the expressions of brain-derived neurotrophic factor（ BDNF）,grial cell-lime derived neurotrophic factor（ GDNF） and vascular endothelial growth factor（ VEGF） in the cortex and hippocampus CA1 area of rats. Method： Wistar rats were randomly divided into three groups,Sham operation group,cerebral ischemia reperfusion（ I / R） group,and cerebral ischemic tolerance（ CIP ＋ MCAO） group. The behavioral changes were detected by neurologic deficit scores（ NDS）,the cerebral histopathology was detected by HE staining,and the level of NSE in serum were detected by ELISA. The expressions of BDNF,GDNF and VEGF in cortex,hippocampus CA1 area were measured by immunohistochemical staining. Result： Compared with Sham operation group,I / R group showed significant increases in neurologic deficit scores and the level of NSE in serum,and improved cerebral histopathology injury（ P 0. 01）,notable decreases in positive area and integral absorbance（ IA） in cortex and hippocampus CA1 area at the damage side,but only statistical differences between brain cortexand Sham operation group; Compared with I / R group,CIP ＋ MCAO decreased the neurologic deficit scores（ P 0. 05）,cerebral histopathology injury（ P 0. 05）,and NSE in serum（ P 0. 01）. At the same time,the positive area and integral absorbance（ IA） of BDNF,VEGF in cortex,and CA1 area at the damage side increased obviously（ P 0. 01,P 0. 05）. The positive expression of GDNF showed an increasing trend,but with no statistical difference. Conclusion： The neuroprotective effects of CIP were correlated with the up-regulation of the endogenous proteins BDNF and VEGF.