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目的许多研究已证实成年鼠脑缺血后神经细胞再生增加,但新生鼠脑缺氧缺血后神经细胞再生如何尚不太清楚。本文旨在调查新生鼠脑缺氧缺血后神经再生情况。方法24只7日龄新生鼠分为对照组(n= 8)和缺氧缺血组(n=16),缺氧缺血组于缺氧后24h行MR扫描以证实脑梗塞灶产生。术后或缺氧后第2～6天每日腹腔注射1次BrdU标记新生的细胞,应用免疫荧光法检查缺血缺氧后1周和4周时神经再生情况。结果缺氧缺血后1周或4周时缺血侧脑室管膜下区(SVZ)明显增宽。缺血侧SVZ的BrdU阳性细胞数在缺氧缺血后1周时显著高于对照组和非缺血侧(P<0.05),缺氧缺血后4周时较1周时下降,但仍显著高于对照组(P<0.05)。缺血侧海马齿状回颗粒细胞层下区(SGZ)的BrdU阳性细胞数在缺氧缺血后1周增高,明显高于对照组(P<0.05), 缺氧缺血后4周时较1周时减少,但仍显著高于对照组(P<0.05)。缺氧缺血后1周或4周时在皮质和纹状体梗塞坏死灶周围可见散在分布的BrdU阳性细胞。结论新生鼠与成鼠类似,脑缺氧缺血后神经再生增强,提示不成熟脑具有一定自身修复能力。
PURPOSE Many studies have demonstrated that the regeneration of neural cells in adult rats increases after cerebral ischemia, but it is unclear how the neurons regenerate after hypoxic-ischemic brain damage in neonatal rats. This article aims to investigate the newborn rat brain after hypoxic-ischemic nerve regeneration. Methods Twenty-four newborn rats of 7 days old were divided into control group (n = 8) and hypoxic-ischemic group (n = 16). MR imaging was performed 24h after hypoxia to confirm cerebral infarction. BrdU-labeled neonatal cells were injected intraperitoneally once a day or 2 days after hypoxia, and the nerve regeneration was examined by immunofluorescence at 1 week and 4 weeks after hypoxia. Results The ischemic subventricular zone (SVZ) was significantly enlarged at 1 week or 4 weeks after hypoxia-ischemia. The number of BrdU positive cells in ischemic SVZ group was significantly higher than that in control group and non-ischemic group at 1 week after hypoxic-ischemic (P <0.05), but decreased at 4 weeks after hypoxic-ischemic insult Significantly higher than the control group (P <0.05). The number of BrdU positive cells in SGZ of ischemic hippocampus increased at 1 week after hypoxia-ischemia, which was significantly higher than that of control group (P <0.05) 1 week, but still significantly higher than the control group (P <0.05). Sporadic distributions of BrdU positive cells were observed around the infarct necrosis of the cortex and striatum at 1 week or 4 weeks after hypoxic-ischemia. Conclusions Newborn rats are similar to adult mice, with enhanced neurogenesis after hypoxic-ischemic brain injury, suggesting that immature brain has some self-repair ability.