肺炎链球菌脑膜炎海马神经发生实验观察

Neurogenesis in the hippocampus in experimental Streptococcus pneumoniae meningitis

目的探讨内源性神经干细胞在幼年大鼠肺炎链球菌性脑膜炎海马的增殖情况。方法建立3周龄大鼠肺炎链球菌性脑膜炎感染组、对照组和假手术组,分别于接种后1、5、14及21d处死大鼠,采用免疫组化方法检测作为神经干细胞的间接标记物的5-溴脱氧尿核苷(bromodeoxyuridine,Brdu)的表达,观察内源性神经干细胞在海马的增殖情况。结果感染组、对照组及假手术组大鼠在接种后d1、d5、d14及d21时双侧海马均可见Brdu阳性细胞,感染组感染后24h,Brdu阳性细胞开始增加,但与d5、d14比较差异无统计学意义(P>0.05),而d5Brdu阳性细胞明显增加,与d14比较差异有统计学意义(P<0.05),Brdu阳性细胞在d14开始下降,d21下降更明显,但仍高于正常水平,与对照组及假手术组比较差异有统计学意义(P<0.05)。结论肺炎链球菌性脑膜炎可刺激幼年大鼠海马神经干细胞的增殖。

Objective To investigate the proliferation of endogenous neural stem cells in the rat brain during experimental Streptococcus pneumoniae meningitis.Methods Three weeks old rats were used to construct the infection group of Streptococcus pneumoniae meningitis,the control group via saline injection,and the sham-operation group.The expressions of bromodeoxyuridine(Brdu)in the hippocampus of the rats were dynamically detected by immunohistochemical method in 24 h,5,14,and 21d after injection,respectively.Results Brdu positive cells were observed in the hippocampus of the infection group of Streptococcus pneumoniae meningitis,the control group,and the sham-operation group at d1,d5,d14,and d21 of inoculation.In the infection group of Streptococcus pneumoniae meningitis,the number of Brdulabeled cells at 24 h after infection was not changed compared to d5 and d14 level(P>0.05),but was greater than d21 level(P<0.05).Compared with the control and the sham-operation group,Brdu positive cells in Streptococcus pneumoniae meningitis rats were increased at 24 h post-infection,reached a peak at d5,then decreased,but still was greater than normal(P<0.05).Conclusion Streptococcus pneumoniae meningitis stimulated the proliferation of endogenous neural stem cells in the hippocampus of the rat brain.