大鼠严重烧伤后心肌细胞GRP94表达变化及其意义

Severe Burn Induces Endoplasmic Reticulum Stress in Rat Cardiomyocytes

目的观察严重烧伤大鼠心肌细胞内质网应激蛋白表达的改变及其意义,以探讨严重烧伤后心肌损伤与内质网应激的关系。方法建立大鼠30%Ⅲ度烫伤模型,酶联免疫法检测血浆中心肌肌钙蛋白T(cTnT)含量,放射免疫法检测血浆中TNFα的含量,RT-PCR和免疫组化分析GRP94的表达。结果烧伤组大鼠伤后3 h血浆中cTnT含量即呈显著升高(P<0.01),心肌中GRP94 mRNA和蛋白表达于烧伤后3 h显著性升高,12 h达峰值,24 h还呈显著升高;大鼠烧伤后3 h心肌中Caspase-3活性开始升高,12 h达高峰,48 h后仍显著高于对照组。牛磺酸治疗组GRP94的表达和Caspase-3活性较烧伤组均有显著性降低(P<0.05)。结论严重烧伤可引起心肌细胞内质网应激,牛磺酸对烧伤后早期心肌损害有保护作用。

Objective To study the effect of severe bums on induction of endoplasmic reticulum stress in rat cardiomyocytes. Methods Healthy adult Wistar rats were randomly divided into the control group （without bums）, the bum group（subjected to a 30% total body surface area （TBSA）Ⅲ degree scalding） and the treatment group （treated with intrapefitoneal injection of taurine （200 mg/kg） immediately after scald injury）. The myocardia tissue samples were harvested at 1, 3, 6, 12 and 24 postbum hours （PBH）. The cardiac troponin T （cTnT） and tumor necrosis factor alpha （TNFα） contents of blood plasma were measured by enzyme linked immunosorbent assay method （ELISA） and radioimmunoassay （RIA）, respectively, RT-PCR and immunohistochemistry were applied to monitor the gene expression changes of glucose-regulated protein 94（ GRP94）. Results The content of cTnT of blood plasma rose siguificanfly within 3 pesthurn hours （ P 〈 0.01 ）, the gene expression of GRIX）4 and caspase-3 activity in 3 postburn hours rose and reached a peak after 12 h, while the GRP94 gene expression fell down dramatically in the group receiving taurine treatment. Conclusion Severe burn can induced endoplasmic reticulum stress in rat cardiomyocytes. Taufine has notable protective effect on the myocardial injury during the early posthum stage.