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目的 观察大鼠脑缺血再灌流时胶质源性神经营养因子 (GDNF)在脑组织的分布特点 ,及其在缺血性脑损伤中的作用。方法 阻断大鼠大脑中动脉 (MCA)血流 2小时 ,再灌流 0 .5～ 48小时制成局灶性脑缺血模型 ,HE染色评价缺血性脑损伤的组织学特点 ,免疫组化法观察GDNF在脑组织的分布特点。结果 再灌流 0 .5小时组有灶性缺血区 ,2 4小时组面积最大 ,包括视前区、纹状体和皮质。再灌流 6小时组开始出现神经元不可逆变性 ,2 4小时组梗死形成。再灌流 0 .5小时组 ,缺血区皮质神经元GDNF弱阳性 ,缺血周边区中等阳性 ;再灌流 3～ 48小时组 ,缺血区神经元GDNF阴性。再灌流 48小时组视前区的梗死周边区巨噬细胞GDNF呈强阳性。GDNF阳性细胞计数显示缺血区各实验组与正常组相比均减少 (均P <0 .0 1) ;2 4小时和 48小时组分别与 0 5小时组和 3小时组相比 ,GDNF阳性细胞数减少 (分别P <0 .0 1)。结论 缺血性脑损伤时 ,变性死亡的神经元GDNF不表达 ,存活的神经元和活化的小胶质细胞或巨噬细胞的GDNF表达增加
Objective To investigate the distribution of glial cell line-derived neurotrophic factor (GDNF) in brain tissue and its role in ischemic brain injury after cerebral ischemia-reperfusion in rats. Methods The focal cerebral ischemia model was established by blocking the flow of rat middle cerebral artery (MCA) for 2 hours and the reperfusion 0.5 ~ 48 hours. HE staining was used to evaluate the histological features of ischemic brain injury. Immunohistochemistry Method to observe the distribution of GDNF in brain tissue. Results In the 0.5 hour reperfusion group, there was focal ischemic area, with the largest area in 24 hours group, including the preoptic area, striatum and cortex. At 6 hours after reperfusion, neuronal irreversible degeneration began to occur and infarction was formed in 24 hours. At 0.5 hour after reperfusion, GDNF in ischemic cortical neurons was weakly positive and moderately positive in ischemic peripheral areas. GDNF neurons in the ischemic area were negative after reperfusion for 3 to 48 hours. Reperfusion 48 hours in the preoptic area infarction peripheral macrophage GDNF was strongly positive. The number of GDNF-positive cells in the ischemic area was significantly lower than that in the normal group (all P <0.01). In 24 hours and 48 hours group, the GDNF positive rate was significantly higher than that in the 0 5 hours and 3 hours group The number of cells decreased (P <0.01, respectively). Conclusions In ischemic brain injury, GDNF is not expressed in degenerative neurons, GDNF expression is increased in surviving neurons and activated microglia or macrophages