单纯性脑震荡大鼠海马OX-42阳性小胶质细胞的表达

Expression of OX-42 positive microglia in the hippocampus of rat after pure cerebral concussion

目的:观察单纯性脑震荡(pure cerebral concussion,PCC)大鼠脑内海马小胶质细胞(microglia,MG)的反应和变化,探讨小胶质细胞是否参与脑损伤后的病理变化以及变化规律。方法:采用清醒状态下自制金属单摆闭合式脑损伤打击装置制备PCC模型,致伤后随机分为3 h、12 h、1 d、2 d、3 d、7 d组(n=5),另设正常对照组(n=5)。采用小鼠抗鼠OX-42单克隆抗体(MG特异性标记物)进行免疫组织化学SP法(streptavidin-peroxidase,SP)和免疫荧光染色,观察PCC组和正常组大鼠海马CA1～4区和上、下齿状回OX-42的表达变化。结果:正常状态下,OX-42表达很少甚至很难发现,PCC组大鼠海马CA1～4区和上、下齿状回的OX-42的表达呈现伤后逐渐增高趋势,与正常组比较有显著性差异(P<0.05),7 d后有下降趋势,但仍高于正常组。结论:PCC损伤早期海马MG出现激活后的形态和数量的变化,提示MG参与PCC致伤后的病理变化。

Objective： To investigate the responses and changes of the microglia （MG） in rat hippocampus after pure cerebral concussion（PCC） and to explore whether microglia are involved in the pathological changes and its changing characteristics after brain injury. Methods ： Under the waking state, rat models of PCC were created by using a self-made metallic pendulum-striker concussive device. The rats were randomly divided into 3 h, 12 h, 1 d, 2 d, 3 d and 7 d（n = 5 for each time point）groups after injury. One control（normal） group（n =5） was used. To observe the distribution and immuno-expression changes of OX-42 in hippocampal areas including CA1 -4 and dentate gyrus between the PCC group and the control group, the immunohistochemical staining（SP） and immunofluorescence staining were used with anti-OX- 42 monoclonal antibody（ special marker for MG）. Results： The results showed that OX-42 immunoreactivity was rarely, and even diffieuh to observed in normal group. The expression of OX- 42 appeared to increase gradually from 3 h to 3 d in the CA1 -4 of hippocampal areas and dentate gyrus after brain injury showing a significant increase when compared with the control ; and showed a downward, but still at higher level trend compared with the control after 7 d. Conclusion The results that MG were activated with the changes in morphology and quantity in the hippocampus during the early stages of injury suggest that MG may be involved in pathological changes after the PCC.