脑梗死后自体神经干细胞原位增殖与分化的实验研究

目的研究成年大鼠脑梗死后自体神经干细胞的原位增殖和分化。方法雄性Wistar大鼠共112只，分对照组(12只)、脑梗死后1d组(20只)、脑梗死后3d组(20只)、脑梗死后7d组(20只)、脑梗死后14d组(20只)、脑梗死后28d组(20只)。大鼠于不同的时间处死，并取出大脑，处死前均注射5-溴胱氧腺苷嘧啶(BrdU)。用免疫组织化学方法动态检测BrdU、Musashil、胶质纤维酸性蛋白(GFAP)、神经元核性蛋白(NeuN)的表达。BrdU、Musashil确定神经干细胞的增殖，GFAP、NeuN确定神经干细胞的分化。结果与对照组相比，大鼠海马BrdU^ 细胞和BrdU^ ／Musashil^ 细胞数在脑梗死后1d组开始增加，7d组达到高峰，28d组接近正常水平；BrdU^ ／GFAP^ 细胞数无明显变化；BrdU^ ／NeuN^ 细胞数在脑梗死后14d组开始增加，28d组最多。结论大鼠脑梗死激活自体神经干细胞原位增殖，并且大多数增殖的神经干细胞分化成神经元。

Proliferation and differentiation of neural stem cells after cerebral infarction: an experimental study of adult rats

Objective To investigate the proliferation and differentiation of neural stem cells after cerebral infarction(CI) in adult rats. Methods CI animal model was made by ligating the common carotid artery and external carotid artery and inserting a piece of nylon thread into the internal carotid artery among 100 male Wistar rats. Then the rats were randomly divided into 5 groups: group of I day after brain infarction (n=20), group of 3 days after brain infarction (n=20), group of 7 days after brain infarction (n=20), group of 14 days after brain infarction (n=20), and group of 28 days after brain infarction (n=20). Twelve rats undergoing sham operation with a piece of nylon thread inserted only into the common carotid artery were used as controls. The rats were killed at different time points and their brains were taken out. The expression of bromodeoxyuridine (BrdU) and Musashil (both used to mark the dividing neural stem cells), and of glial fibrillary acidic protein (GFAP) and neuronal nuclear antigen (NeuN) (both used to mark the differentiating neural stem cells) were determined by immunohistochemistry and immunofluorescence staining. Results In the normal brain tissues, only a small amount of BrdU+ cells were found in the hippocampus. One day after CI the number of BrdU+ cells began to increase in the hippocampus at the CI side (P<0.05), peaked 7 days after CI with a number 6 times that at the normal side, began to decrease 14 days after, and almost reached normal 28 days after. The number of BrdU+/Musashil+ cells began to increase 1 day after CI (P<0.05), peaked 7 days after, began to decrease 14 days after, and almost reached normal 28 days after. The number of BrdU+/GFAP+ cells at the CI side remained almost unchanged after CI. The number of BrdU+/NeuN+ cells began to increase 14 days after CI (P<0.05) and peaked 38 days after. Conclusion Cerebral infarction stimulates the proliferation of inherent neural stem cells and most proliferated neural stem cells differentiate into neurons.