大鼠钝力性脑挫伤后PSD-95的表达

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

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。

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.