新生鼠缺氧缺血性脑损伤后经脑室人神经干细胞移植的实验研究

Transplantation of human fetal neural stem cells into cerebral ventricle of the neonatal rat following hypoxic-ischemic injury: survival, migration and differentiation

目的研究新生鼠缺氧缺血性脑损伤后经脑室移植人胚胎脑神经干细胞后,植入细胞的存活、迁移及分化情况。方法孕12周人胚胎神经干细胞在含有碱性成纤维细胞生长因子、表皮细胞生长因子和白血病细胞抑制因子的N2培养基(D/F12+N2+B27)中培养11天。生后7天的新生SD大鼠32只建立缺氧缺血性脑病模型,3天后将培养的人神经干细胞制成悬液(1.0×105/μl),采用立体定向移植至实验动物损伤侧脑室。移植后1、2、4周及3个月(每时间点各8只)取脑组织行HE染色和免疫组织化学分析。结果移植后1周大量抗人细胞核蛋白抗体阳性的植入细胞从脑室沿胼胝体向外迁移并到达损伤区,以损伤侧皮层、海马多见,在不同区域可见与宿主细胞类似的分化的植入细胞:移行至皮层的植入细胞85%分化为抗人细胞核蛋白神经丝蛋白或抗人核蛋白神经元管蛋白抗体双阳性的皮层细胞,而位于移行区域的植入细胞60%表达为抗人核蛋白胶质纤维酸性蛋白抗体双阳性的星形胶质细胞,其余细胞仍在迁移中未分化。移植后2周更多的移植细胞到达损伤区,移植后4周及3个月植入细胞数较前明显减少。结论人胚胎神经干细胞经脑室移植至缺氧缺血性脑损伤的鼠脑后能存活、迁移,并依迁移区域的不同分化为神经元和星形胶质细胞。

Objective Neonatal hypoxic-ischemic encephalopathy （HIE） harms the lives and health of newborn infants and children severely. Given the absence of effective therapies for HIE, it is important to derive new strategies. Neural stem cells （ NSCs ） have great potential as a therapeutic tool for the repair of a number of central nervous system disorders that involve cell loss. This study was designed to transplant the neural stem cells derived from human fetal brain （ hNSCs ） into cerebral ventricle of neonatal rat following hypoxic-ischemic injury and to investigate their survival, migration and differentiation in rat brain. Methods Cells obtained from the forebrain of a 12-week old fetus were cultured in the presence of epidermal growth factor, basic fibroblast growth factor and leukemia inhibitory factor for 11 days. Animal models were built in 7-day-postnatal Wistar rats, 3-days after hypoxia-ischemia （ HI ）, 5 μl suspensioncontaining 5.0 × 10^5 hNSCs was injected into the left cerebral ventricle of each HIE rat by using stereotactic instrument. No immunosuppression therapy was given to the animals. At 1, 2, 4 weeks and 3 months after transplantation, the rats were sacrificed and brain tissues were harvested and were then examined by H-E staining and immunohistoehemical analysis. Results Implanted cells expressing human nuclear protein（hNP） migrated form the subventricular zone （SVZ） along corpus callosum to the damaged areas, especially to the injured side of cortex and hippocampus. In different areas, the implanted hNSCs differentiated into different cell types which were similar to the host cells. The 85% implanted cells in cortex consisted of hNuc-NF or hNuc-Tublin double positive cells, while in the migratory way, 60% implanted cells differentiated into hNuc-GFAP double positive cells. Compared with the 1-week time point, an increased number of hNP-positive cells were observed at 2-weeks, but the number of these cells greatly decreased at 4-weeks and 3 months. Conclusion The implanted hNSCs could extensively survive, migrate in the brain of neonatal rat with HIE and could differentiate into neurons and astrocytes in a regionally specific manner.