严重烫伤早期脑内星形胶质细胞与GFAP表达的变化

Changes of Astrocytes and GFAP Expression in the Early Stages of Severe Scalded Rats

目的:探讨星形胶质细胞形态变化及胶质原纤维酸性蛋白(GFAP)表达与严重烫伤引起的血脑屏障损伤之间的关系。方法:健康SD大鼠,随机分为正常组、烫伤组(分3、6、12、24、48h5个时相点),用透射电镜观察血脑屏障超微结构变化;紫外分光光度计检测脑伊文蓝(Evan’sBlue,EB)含量。免疫组化观察脑GFAP表达。结果:正常组星形胶质细胞结构清楚,各种细胞器完整。烫伤后3h线粒体肿胀,空泡化。严重烫伤后脑EB明显高于正常组(P<0.01),以6～12h最为明显,24h后开始下降。GFAP的阳性表达定位于星形胶质细胞的胞浆及突起内,呈棕褐色或棕黄色。GFAP阳性细胞轮廓清楚,细胞突起成星形。烫伤后GFAP阳性细胞数目明显增多,染色增强,平均光密度增高﹙P<0.01),12～24h达高峰且形态不规则,48h后开始下降。结论:严重烫伤后星形胶质细胞活化、GFAP表达增加与血脑屏障通透性增高有关,提示GFAP在严重烫伤早期对血脑屏障的损伤有重要作用。

Objective： To explore the relationship between morphologic changes of astrocytes and glial fibrillary acidic pro- tein （GFAP） expression and blood-brain barrier （BBB） after severe scald in rats. Methods： Healthy SD rats were divided into three groups,normal control, scald group and sham-scald group. The uhrastructural change of BBB was observed by transmis- sion electron microscope at 3, 6, 12, 24 and 48 h after thermal injury. The Evans blue content in brain was examined with the ultraviolet spectrophotometer. The changes of brain GFAP expression were determined by immunohistochemieal method. Resuits： Under transmission electron microscope, mitoehondrion of astroeytes of the cerebral cortex was swollen andvacuolated 3 h after thermal injury. Brain Evans blue content and expression of GFAP were significantly increased after severe scald （P 〈 0.01）. Conclusion： The increases in GFAP expression and astroeyte activation were associated with increased BBB permeability following thermal injury, which indicated that GFAP may contribute to observed BBB disruption in peripheral thermal injury.