大鼠弥漫性脑损伤神经元HSP70表达及神经髓鞘的病理变化

An experimental study of HSP70 expression and morphology of myelin sheath after diffuse brain injury in rats

目的探讨脑神经元HSP70表达变化和神经髓鞘病变在弥漫性脑损伤(DB I)诊断及其损伤时间判断的价值。方法将50只SD大鼠分为正常对照组和DB I组,后者按DB I后处死大鼠的时间不同又分为0.5h、1h、3h、6h、12h、1d、3d、7d及10d组。然后复制大鼠DB I模型,脑组织常规取材后进行HSP70免疫组化及劳克坚牢蓝(LFB)髓鞘染色,观察神经元HSP70的变化和神经髓鞘病变。结果大鼠DB I后0.5h,脑干及海马处见HSP70免疫组化染色阳性的神经元;伤后1h明显,12h达到高峰,1d下降,7d基本恢复正常。神经髓鞘于伤后0.5h开始逐渐出现水肿,分层、碎裂及聚集成团块状,伤后1d最明显,3d后开始逐渐减退,10d基本正常。结论神经元HSP70表达变化和神经髓鞘病变程度对DB I诊断及其损伤时间判断具有一定的参考价值。

Objective To study HSP70 expression and morphological changes of myelin sheath in rat after experimental DBI in order to explore a useful method to estimate the injury time of DBI. Methods Fifty SD rats were divided into a normal control and 9 different injury groups at 0.5h, lh, 3h, 6h,12h,ld, 3d,7d, 10d after the DBI. The animal models of DBI was made according to the method described by Marmarou. The HSP70 expression and the morphological changes of myelin sheath in each groups were observed by immunohistochemical （ SABC method） and LFB staining. Results In brain tissue of normal control group, no significant change was found. In the brain tissues of injury groups, the HSP70 expression showed a time-dependent difference as fellows： It began at 0.5h, increased at 3h and reached to maximize at 12h, then decreased, and returned to the basal level on 1 d. Meanwhile, the morphologic changes of myelin sheath stained by LFB showed edema, delamination, broken and collected into piles in brain stem at 0.5h, those morphological changes reached the peak on ld, decreased and began reparation on 3d, and recovered to normal station basically on 10d after the DBI. Conclusion The HSP70 expression and morpho- logical changes of myelin sheath in rat observed by immunohistochemical and LFB staining can be used to help the diagnosis of DBI and estimation of injury time of DBI