大鼠脑创伤后小胶质细胞激活的时程及形态变化研究

Changes in Morphology and Time Course of Activated Microglias in Rats with Brain Injury

目的探讨大鼠脑创伤后小胶质细胞激活的时程及形态变化。方法采用改良的Feeney等人的方法造成大鼠颅脑损伤模型,21只SD大鼠随机分为对照组和创伤组,后者根据伤后处死时间点不同,再分为伤后1h,6h,12h,24h,48h和72h组,每组动物3只,在伤后不同时间点处死动物,取伤区脑组织行抗OX-42免疫组织化学染色。结果正常大鼠脑内小胶质细胞一般为静息状态,OX-42为阴性,在切片上不易发现或细胞形态不清晰;伤后1h,小胶质细胞为轻度反应,OX-42浅染,细胞形态隐约可见,不规则;伤后6h,小胶质细胞反应明显,由静息状态变为早期反应状态,OX-42深染,细胞形态清楚;伤后12h,小胶质细胞反应达高峰,细胞形态更清楚,突起上可见到小棘;24h以后,反应减弱,OX-42浅染,细胞数量减少。结论大鼠脑创伤后小胶质细胞被激活,细胞形态发生改变,海马区亦有激活改变;反应的时程变化是伤后1h出现激活,6h反应明显,12h达高峰,以后逐渐减弱。

Objective To investigate the changes in the morphology and the time course of activated microglias in rats with brain injury. Methods The eraniocerebral injury model was established hy Feeney et al method. Twenty-one SD rats were randomly divided into control group （n=3） and traumatic group （n=18）, which was divided into 6 subgroups according to the time when the animals were sacrificed after the craniocerebral injury. Immunohistochemical SABC method was used to determine the expression of OX-42 in the injured brain tissues. Results In the control group, the microglias of brain tissues kept quiescent condition, OX-42 staining was negative or light, and the cells features were unclear or could not be observed. The microglias manifested light response, and OX-42 was light stained, OX-42 cells were found but their feature were unclear 1 hour after the injury. The response of microglias was obvious, OX-42 staining manifested anachromasis 6 hours after the injury. The response of microglias peaked, the cells features were clear, and the spines on the cellular processes were clearly found 12 hours after the injury. The response of microglias decreased, and OX-42 was light stained again 24, 48 and 72 hours after the injury. The early microglia response was also observed in the hippocampal CA1 area after the injury. Conclusions The microglias in the injured brain tissues begin to be activated 1 hour after the injury. The response of microglias in the injured brain tissues becomes significant 6 hours after the injury, peaks 12 hours after the injury and tapers ever since.