宫内感染致脑损伤对仔鼠认知发育和海马神经发生的影响

 目的:探讨宫内感染致仔鼠脑损伤后对认知发育和海马神经发生的影响。方法: 15只Sprague-Dawley孕鼠（孕15 d）按随机数字表法分为造模组（8只）和对照组（7只）。繁殖后的2组雄性仔鼠按随机数字表法分为宫内感染组（35只）和对照组（35只），进行大脑解剖学观察、神经细胞凋亡检测、Morris水迷宫实验、神经细胞增殖及存活分析。结果: （1）宫内感染组仔鼠大脑较对照组萎缩，TUNEL阳性细胞数和caspase-3阳性细胞数均较对照组显著增加 (P<0.05)。（2）宫内感染组仔鼠近期记忆及远期记忆保持能力均较对照组降低，潜伏期显著延长（P<0.05）。（3）细胞增殖分析显示宫内感染组3 、7 和14日龄仔鼠BrdU阳性细胞数较对照组显著增加（P<0.05）；细胞存活分析显示，28日龄的2组仔鼠BrdU阳性细胞数无显著差异（P>0.05）。结论: 宫内感染可致仔鼠脑损伤，海马神经细胞凋亡可能与认知发育障碍密切相关。宫内感染诱导的神经发生可能与脑损伤后神经自身修复有关。

Brain injury induced by intrauterine infection affects offspring’s cognitive development and hippocampal neurogenesis

AIM: To explore the effect of brain injury induced by intrauterine infection on offspring’s cognitive development and hippocampal neurogenesis. METHODS: Sprague-Dawley pregnant rats (n=15) were randomly divided into model group (n=8) and control group (n=7). After delivery, the male pups were randomly divided into E. coligroup (n=35) and control group (n=35). Total 20 male pups at postnatal day 28 (P28) were randomly divided into 2 groups for Morris water maze test. Hippocampi of the 2 groups were used for cell apoptosis, neuronal proliferation and survival analysis. RESULTS: (1) The brain tissue was slightly atrophied in E. coligroup. The numbers of TUNEL and caspase-3 positive cells were significantly increased in E. coligroup (P<0.05). (2) In the navigation and memory task, the rats in E. coligroup had longer escape latency than that in control group (P<0.05). (3) There was a significant increase in the BrdU-labeled cells at P3, P7 and P14 in E. coligroup than that in control group (P<0.05). When the cells got mature, no significant difference of BrdU-labeled cells at P28 between the 2 groups was observed (P>0.05). CONCLUSION: Intrauterine infection increases hippocampal neuronal apoptosis, which may be regarded as an etiological factor in the cognitive development impairment. Inflammation-induced neurogenesis may play an important role in neuronal protection and repair in immature brain after intrauterine infection.