解耦联蛋白2在急性肝功能衰竭大鼠肝脏中的动态表达和意义

Dynamic expression of uncoupling protein 2 in rats models of acute liver failure and its significance

目的探讨急性肝功能衰竭（ALF）大鼠肝脏线粒体解耦联蛋白（UCP）2的表达趋势及意义。方法健康雄性SD大鼠36只，分为对照组和模型组，模型组再分为6、12、24、36和48h5个亚组，每组6只。模型组腹腔内注射D-氨基半乳糖（D-Gal）和脂多糖（LPS）诱导大鼠ALF模型。采用HE染色，光学显微镜下观察肝组织损伤情况，采用RT—PCR和免疫组织化学检测不同时间点肝脏UCP2mRNA转录及其蛋白表达，同时测定各时间点血清ALT、AST和肝组织丙二醛（MDA）的变化。各实验组间数值比较采用SNK检验。结果模型组肝组织呈炎性细胞浸润和明显坏死的ALF特征；模型组ALT、AST、MDA值均明显高于对照组[（24．0±2．0）U／L，（82．3±16．9）U／L，（2．55±0．22）μmol／g]，且造模24h达高峰[（8346．7±1363．1）U／L，（9766．7±1274．1）U／L，（8．34±1．13）μmol／g；均P〈0．05]；UCP2蛋白和UCP2mRNA在正常肝组织中几乎不表达，D-Gal和LPS处理后6h表达均显著增加（P〈0．06），24h表达最强，且模型组相邻时间点之间差异有统计学意义（P〈0．05）。结论成功构建大鼠ALF模型，大鼠ALF时UCP2蛋白和UCP2mRNA的表达水平与肝损伤程度及氧化应激水平有关。

Objective To explore the expression and significance of uncoupling protein （UCP）2 in rats models of acute liver failure （ALF）. Methods Thirty-six healthy male SD rats were randomly divided into normal control group and model group, and the model group was divided into 5 subgroups： 6, 12, 24, 36 and 48 hours sub groups with 6 rats in each sub group. The rat model of ALF was established by intraperitoneal injections of D-galactosamine （D-Gal） and lipopolysaccharide （LPS）. Sections of liver tissue were stained with hematoxylin and eosin and observed under optical microscope. UCP2 and UCP2 mRNA in rat liver were determined at different time points with immunohistochemical method and reverse transcription-polymerase chain reaction （RT-PCR）, respectively. Serum alanine aminotransferase （ALT） and aspartate aminotransferase （AST） levels and malondialdehyde （MDA） concentration in the liver tissues were analyzed at the same time points. Comparisons among all the experimental groups were done by SNK test. Results Infiltration of inflammatory cells and necrosis of hepatic cells were marked in model group, and ALT, AST and MDA in model group were significantly higher than those in control group [（24. 0±2. 0） U/L, （82. 3±16.9） U/L, （2.55±0.22） μmol/g] at all time points. And they reached a peak at 24 h [（8346.7±1363.1） U/L, （9766. 7±1274. 1） U/L, （8. 34±1. 13） μmol/g; all P〈0.051. UCP2 and UCP2 mRNA expressed scarcely in the liver tissues of control group, while increased markedly from 6 to 48 hours after D-Gal/LPS challenge in model group （P〈0.05）. They both reached a peak at 24 h. And the discrepancy between consecutive experimental group had statistical significance （P〈 0.05）. Conclosions The rat model of ALF was established successfully by intraperitoneal injections of D-gal and LPS. The expression levels of UCP2 mRNA and UCP2 are consistent with the extent of liver injury and the level of oxidative stress in the rat model of ALF.