大鼠脑外伤后脑组织MMP-9的表达与损伤时间相关性

目的观察大鼠脑外伤后脑组织MMP-9的表达规律,探讨其在损伤时间推断中的应用价值。方法健康SD大鼠75只,随机分为损伤组、假损伤组和正常对照组。损伤组采用自由落体方法建立脑损伤模型;致脑损伤后分10个时间点,采用HE染色观察损伤区的变化,采用免疫组化方法检测各时间点阳性细胞的种类和比值,并与假损伤组和对照组进行统计分析比较。结果免疫组化染色显示损伤组伤后1h可见中性粒细胞阳性着色,6h后可见神经细胞阳性染色并逐渐增强,伤后5d阳性细胞数达到峰值,而后开始减弱,14d基本消失。假损伤组和正常对照组未见阳性表达。将实验组中2h～7d阳性细胞比值与其它各时间点相比,差异有统计学意义(P<0.05);实验组各时间点与假损伤组和对照组相比,差异均有统计学意义(P<0.05)。统计分析结果见表1。结论损伤后MMP-9阳性表达的规律性,有望成为脑损伤时间判定的参考指标。

Relationship between estimation of injury time and MMP-9 expression after brain injury in rats

Objective This study was carried out to explore the application value of MMP-9 expression in the deduction of injury time by examining the regulation of MMP-9 expression at different time points after the rats were injured.Methods 75 healthy SD rats were assigned into 3 groups,e.g.injury group,false injury group and control group randomly.The brain injured model was established by beating the exposed region of brain with a free falling device in the injury group.The histology changes of the injury region in the brain were observed by HE staining at 10 different time points after beating.At the same time,the ratio and types of positive expression cells were detected by immuno-histochemistry method at different time.Then the results were analyzed with the other 2 groups.Results After immuno-histochemical staining in the injury group,MMP-9 expression was examined positively in Neutrophils at 1h after injury.And MMP-9 expression was examined positively in Nerve cells after 6h later and increasing gradually until the positive expression reaching the peak at the 5th day.Since then decreased,and it nearly disappeared at 14th day after injury.But there was no distinct positive expression in the false injury group and the normal control group.In the experimental group,the ratios of positive expression cells in 2h~7d after injury were significant difference(P< 0.05) compared with other points of time.And the differences of the ratios of positive expression cells were statistically significant(P< 0.05) examined at every time points in the experimental group compared with both of the false injury group and the normal control group.Conclusion The results indicated that MMP-9 were often expressed in the injured tissue regularly,and this pattern could be a reference indicator to estimate the time of brain injury.