肺炎链球菌脑膜炎室管膜下区神经发生的实验观察

Neurogenesis in the subventricular zone in the course of experimental Streptococcus pneumoniae meningitis

目的观察内源性神经干细胞在幼年大鼠肺炎链球菌性脑膜炎室管膜下区的增殖。方法 3周龄SD大鼠分为感染组(n=28)、对照组(n=16)和假手术组(n=16)。感染组脑池穿刺接种肺炎链球菌,对照组注射生理盐水,假手术组仅剪开皮肤,分别于接种后24 h,及5、14及21天各处死4只大鼠,采用免疫组化法检测神经干细胞间接标志物5-溴脱氧尿核苷(Brdu)的表达,观察内源性神经干细胞在室管膜下区的增殖情况。结果感染组、对照组及假手术组大鼠在接种后第24小时、5天、14天及21天时,双侧室管膜下区均可见Brdu阳性细胞,感染组的Brdu阳性细胞在接种后24小时开始增加,第5天达到高峰,随后逐渐下降,各时间点的差异有统计学意义(P<0.05)。在接种后24小时、5天和14天时,感染组的Brdu阳性细胞数均高于对照组及假手术组,差异有统计学意义(P<0.05);接种后第21天时,感染组与对照组的差异无统计学意义(P>0.05),但与假手术组的差异仍有统计学意义(P<0.05)。结论肺炎链球菌性脑膜炎可刺激幼年大鼠室管膜下区神经干细胞的增殖。

Objective To investigate the proliferation of endogenous neural stern cells in rat brain in the course of experi- mental Streptococcus pneumoniae （Sp） meningitis. Methods Three-week-old SD rats were divided into Sp meningitis group （n= 28）, control group （n=16） and sham operation group （n=16）. The rats in Sp meningitis group were inoculated with Sp by cister- hal puncture and rats in control group were injected with normal saline. Four rats each were individually sacrificed at 24 h, 5, 14 and 21 days after inoculation and the expressions of Bromodeoxyuridine （Brdu） in the subventricular zone and hippocampus of the rats were dynamically detected by immunohistochemical method. Results Brdu positive cells were observed in the bilateral subventricular zone of the rats in Sp meningitis group, control group and sham operation group at 24h, 5, 14 and 21 days after in- oculation. The number of Brdu positive cells in Sp meningitis group was increased initially at 24h after inoculation, reaching a peak at 5~ day and then decreased. There was difference among different time points （P〈0.05）. At 24h, 5 and 14 days after inocu- lation, the number of Brdu positive cells was respectively significantly higher in Sp meningitis group than that in control group and sham-operation group （P〈0.05）. At 2th day after inoculation, the number of Brdu positive cells in Sp meningitis group was similar with control group （P〉0.05）, while different from sham operation group （P〈0.05）. Conclusions Sp meningitis can stimu- late the proliferation of endogenous neural stem cells in the subventricular zone of rat brain.