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目的探讨外源性促红细胞生成素(Epo)对新生鼠缺氧缺血性脑损伤(HIBD)后神经干细胞的影响以及Epo的神经保护机制。方法72只新生7日龄Wistar大鼠随机分为对照组、HIBD组和干预组,每组24只。结扎大鼠右侧颈总动脉和8%低氧暴露2h制备新生大鼠HIBD模型。对照组仅游离右侧颈总动脉,不予结扎和缺氧处理。干预组大鼠缺氧缺血后立即腹腔注射重组人促红细胞生成素(rh-Epo)5000IU/kg,每天1次,连用3d。HIBD组大鼠缺氧缺血后连续腹腔注射等量生理盐水3d。每组随机取8只分别于术后4、7、14d处死。应用免疫组化方法和计算机图像分析技术检测不同时点海马齿状回巢蛋白(nestin)标记阳性细胞的变化。结果各时点HIBD组nestin阳性细胞数较对照组增加(P<0.05);各时点干预组nestin阳性细胞较对照组和HIBD组均增加(P<0.05)。3组大鼠海马齿状回区nestin阳性细胞数均于术后7d达高峰。结论早期给予rh-Epo可促使新生鼠HIBD后海马齿状回区nestin表达增加,促进神经干细胞的增殖再生,在HIBD后神经再生、修复中发挥一定的保护作用。
Objective To investigate the effect of exogenous erythropoietin (Epo) on neural stem cells in neonatal rats after hypoxic-ischemic brain damage (HIBD) and the neuroprotective mechanism of Epo. Methods 72 neonatal 7-day-old Wistar rats were randomly divided into control group, HIBD group and intervention group, 24 rats in each group. HIBD model of neonatal rats was established by ligating right common carotid artery and 8% hypoxia exposure for 2 hours. The control group only free right common carotid artery, not ligation and hypoxia. Rats in the intervention group were injected intraperitoneally with 500IU / kg of recombinant human erythropoietin (rh-Epo) once a day for 3 days after hypoxia-ischemia. Rats in HIBD group were injected intraperitoneally with equal volume of normal saline after hypoxia - ischemia. Eight rabbits in each group were sacrificed at 4, 7 and 14 days after operation respectively. Immunohistochemistry and computer image analysis were used to detect the changes of hippocampal dentate nestin positive cells at different time points. Results At each time point, the number of nestin positive cells in HIBD group was higher than that in control group (P <0.05). The nestin positive cells in intervention group were higher than those in control group and HIBD group at each time point (P <0.05). The number of nestin positive cells in hippocampal dentate gyrus in 3 groups reached the peak on the 7th day after operation. Conclusion Early administration of rh-Epo can promote the expression of nestin in hippocampal dentate gyrus of newborn rats and promote the proliferation and regeneration of neural stem cells, which play a protective role in nerve regeneration and repair after HIBD.