小鼠脑损伤后GFAP表达与损伤时间的关系

The Expressions of GFAP Rat Brain After Mechanical Injury and Its Relation with Injury Time

目的探讨小鼠脑损伤后胶质纤维酸性蛋白(GFAP)在损伤灶周围的大脑皮质及白质的表达和损伤时间的关系。方法将健康KM小鼠48只,按施加的处理不同随机分为4组,分别为正常对照组、手术对照组、死后对照组、损伤组。运用免疫组化的技术方法进行研究以及运用图像分析技术测量GFAP阳性反应的灰度。结果(1)手术对照组及正常对照组、死亡对照组小鼠脑组织内均有低水平GFAP表达,它们之间的差异无统计学意义。(2)机械性脑损伤灶在一定时间后GFAP表达增加,其分布特征与对照组相似。主要分布在损伤灶周围的皮质、白质。(3)GFAP在损伤灶周围皮质、白质的表达曲线非常相似,但在白质的反应更加明显。(4)机械性脑损伤后24 h表达显著增加,168 h后达高峰,其后数天维持在较高水平。结论脑外伤诱导GFAP在损伤灶表达增加,证明它们参与脑损伤修复。在特定损伤部位它们仅主要在星形胶质细胞中表达,从一个侧面反映星形胶质细胞的分裂增殖活动。同时它们之间也可能与脑损伤后神经元活动的存活及维持其功能活动有关。其表达改变的时序可望作为一个客观指标用于法医学脑损伤所经过时间的推断。

Objective To research the expression of GFAP after moderate mechanical brain injury in rats and its relation with injury time. Methods Healthy KM rats were divided into normal control, sham operation control, death control and injury group. There was no other influence on the normal control groups. The expression of GFAP was studied by IHC. Results （ 1 ） In the brain of normal control and sham operation control groups, the low expression levels of GFAP were observed. （2） Mechanical brain injury induced an increase in levels of GFAP. （3） The expression levels of GFAP in the cortex of brain were very similar with the ones in the medulla of brain , but higher in the cortex of brain than in the medulla of brain. （4） The remarkable increasing of GFAP signal could be observed within 24 h after injury, reaching to the peak at 168 h. Conclusions Mechanical brain injury induced an increase in the gene expressions of the GFAP. The results suggested that the GFAP may contribute to the survival of nerve cell and the repair of damaged neural tissues after CNS injury. The patterns of GFAP level change were quite regular and may be used for the timing of injury in forcnsic medicine.