高迁移率族蛋白B1在烧伤小鼠大脑中表达的研究

目的:检测烫伤小鼠高迁移率族蛋白B1(HMGB1)在大脑中的表达.方法:应用BALB/c小鼠15%TBSAⅢ度烫伤(95 ℃热水浸烫8 s)和假伤(室温水,8 s)模型,并以正常小鼠作为对照(6只).在4、8、24和48h(每个时间点6只)处死动物.采用苏木精-伊红染色观察大脑形态学改变,免疫荧光方法检测caspase-3和HMGB1在大脑的表达,ELISA方法检测大脑组织HMGB1含量.结果:15%体表面积Ⅲ度烫伤8 h即导致大脑发生显著性病理改变,如炎性细胞浸润,烫伤24h大脑终纹出现caspase-3阳性细胞,而在假伤组未见特异性染色.免疫荧光染色发现,HMGB1位于假伤组小鼠神经细胞的胞核;而在烫伤后4h即释放至细胞浆.释放到脑组织中的细胞外HMGB1在烧伤后 24和48h,显著高于假伤组和对照组(P<0.01).结论:烫伤导致小鼠大脑HMGB1的分布和含量发生改变,可能参与了烧伤后脑损伤的病理过程.

Expression of high mobility group box 1 protein in the brain of thermal-injured mice

Objective：To investigate the expression of high mobility group box 1 protein （HMGB1） in the brain tissue of thermal-injured mice. Methods： Male BALB/c mice were exposed to 15% total body surface area thermal injury （95 ℃ ,8 seconds） and the brains were collected at 4,8,24,48 hours （n= 6）. Cerebral pathology was examined with hematoxylin/eosin staining, while caspase-3 or HMGB1 positive cells were evaluated with immunofluoreseence and confoeal rffleroscopy. In addition,cerebral HMGB1 content was determined by enzyme linked irnmunoadsorbent assay （ELISA）. Sham-injured rats （room temperature,8 seconds） and normal rats served as controls. Results： Mice under thermal injury exhibited remarkably neuropathological lesions,such as leukocyte infiltration,and caspase-3 positive cells in cerebrum 24 hours postburn. No positive expression of caspase-3 was found in sham-injured group. Positive HMGB1 reactive signal was located in the nuclei in the cortical cells of injured mice,and it was released into the cytoplasm as early as 4 hours postburn. Cerebral HMGB1 content was significantly higher in burn group at 24 and 48 hours postburn compared to that of sham-injured or normal group （P〈0. 01）. Conclusions： Thermal injury per se could result in abnormal distribution and release of HMGB1 into the brain, thereby possibly participating in burn-induced septic eneephalopathy.