神经干细胞移植对HIBD新生大鼠学习记忆的影响

目的：探讨脑内移植胚鼠神经干细胞 (NSCs)对新生大鼠缺氧缺血性脑损伤(HIBD)后学习记忆的影响。 方法： 分离孕龄14 d的Sprague-Dawley（SD）大鼠胚胎前脑皮质，采用无血清悬浮培养的方法获得细胞克隆；7 d龄新生大鼠随机分为假手术组（n=10）、HIBD组（n=11）和移植组（n=13），后两组结扎左侧颈总动脉联合8%氧吸入制作HIBD模型，损伤后3 d利用立体定位仪分别在左侧海马区植入培养基作为对照或BrdU 标记的NSCs，观察植入4 周后大鼠学习记忆功能的恢复情况。计数海马CA1区正常神经元，间接免疫荧光法观察移植细胞在脑内的存活、迁移情况。 结果： 在放射形迷宫测试中，移植组较对照组表现出明显的改善，觅水时间缩短(61.40 s±24.83 s vs 89.32 s±31.52 s)，错误次数（2.65±0.57 vs 3.78±0.41）及重复次数明显减少(0.32±0.43 vs 0.81±0.47)(P<0.05)。BrdU间接免疫荧光显示移植后4周，在脑内可见存活的NSCs在海马内广泛分布；尼氏染色显示移植可明显减少海马CA1区的细胞丢失。 结论： 脑内移植胚鼠NSCs对HIBD新生大鼠的学习记忆恢复有良好的促进作用。

Grafting neural stem cells improve the impaired cognitive deficits and spatial recognition after ischemic-hypoxic brain damage in neonatal rats

AIM: To investigate whether grafting neural stem cells (NSCs) improves the impaired cognitive deficits and spatial recognition after ischemic-hypoxic brain damage (HIBD) in neonatal rats. METHODS: Non-immunosuppressed 7-day-old SD rats were used as research subject and randomly divided into 3 groups: (1) sham group (n=10); (2) HIBD group (n=11); (3) transplant group (n=13). (2) and (3) were anesthetized and subjected to a hypoxic/ischemic injury obtained by combination of left carotid ligation and exposure to 8% oxygen for 2 h. At 3 days post injury, hypoxic-ischemic brain damaged animals were re-anesthetized and randomized to receive stereotactic injection of NSCs prelabeling with BrdU or control media into the hippocampus in the ipsilateral hemisphere. Cognitive (i.e., learning) deficits were assessed at 2 to 4 weeks after transplantation. At the end of the behavioral tests, the animals were killed and evaluated for NSC survival and histopathological analysis. RESULTS: Transplant group showed significantly improved cognitive function in selected tests as compared with HIBD group during the 4-week observation period. They took less time than HIBD group in finding the 3 arms baited with water and had a decreased number of working and reference memory errors in radial maze acquisition tests. Histological analysis showed that transplanted NSCs attenuated CA1 cell loss after HIBD, and NSCs survived for as long as 4 weeks after transplantation and were detected in the hippocampus. CONCLUSION: These data suggest that transplanted NSCs attenuate brain damage and cognitive dysfunction after hypoxic-ischemic brain damage. This approach warrants continued investigation in light of potential therapeutic uses.