大鼠钝力性脑挫伤后PSD-95的表达

目的检测脑挫伤修复过程中突触后致密蛋白(postsynaptic density protein 95,PSD-95)的表达,探讨其变化规律与损伤时间的相关性。方法雄性SD大鼠50只,随机分为8个实验组,1个对照组,每组5只。制作大鼠脑挫伤模型,于伤后3、6、12h和3、5、7、10d取脑组织,应用免疫组织化学技术和免疫蛋白印迹(Western blot)方法检测脑挫伤后不同时间脑组织中PSD-95的表达变化。结果对照组脑组织仅有少量PSD-95阳性细胞;实验组中,伤后3h、6h组脑组织出现较多PSD-95阳性细胞,12h组阳性细胞数量持续升高,伤后1d阳性细胞数下降,5d后又升高并达到高峰,7d、10d恢复;计算阳性率,统计分析结果显示,阳性细胞数与相邻上组比较,存在显著性差异。Western blot结果:挫伤后,3～12h表达量上升,1d下降,随后又逐步上升,5d达到高峰,7d、10d下降;应用Fluorchem V2.0 Stand Alone软件获取感光条带的平均灰度值,经统计分析,各组与相邻上组比较,存在显著性差异。结论大鼠脑损伤后损伤周边区PSD-95呈现升高→下降→再升高→再下降的表达规律,对损伤时间推断有一定的参考意义。

An immunohistochemical study on postsynaptic density protein 95 after brain contusion in rats

Objective To investigate changes of postsynaptic density protein 95(PSD-95) after brain contusion.Methods An animal model of brain contusion was established in rats.Rats were killed under anesthesia with diethyl ether at 3,6,12h,1,3,5,7 and 10d after contusion(5 rats in each group).Five rats without impact were used as control.PSD-95 was detected by immunohistochemical staining and Western blotting.The ratios of the number of PSD-95-positive cells to total number of the cells in the wounded zone were evaluated.Results A few of PSD-95-positive cells were observed in the control group.The number of PSD-95-positive cells began to increase at 3h,peaked at 12h,and then decreased after contusion.The positive cell number maximized again at 5d post-contusion,and then decreased.By statistical analysis,there were significant differences in positive cell ratios between neighboring groups.Weak PSD-95 was detected in control group by Western blot analysis.For the contusion groups,PSD-95 showed the samilar tendency of time-dependent changes as detected by Western blotting.Conclusions PSD-95 reveals a time-dependent changes after brain contusion in rats,suggesting that it may be used as a marker for wound age estimation.