肝组织解偶联蛋白2在梗阻性黄疸及胆道再通实验大鼠模型中的表达及意义

Expression and significance of UCP-2 in rats with obstructive jaundice and bile flow restoration

目的研究梗阻性黄疸及胆道再通大鼠肝组织解偶联蛋白(UCP)2的表达及意义,探讨梗阻性黄疸对能量代谢障碍与氧化损伤的影响。方法 36只健康雄性大鼠随机分为6组,每组6只:假手术组(A组)、梗阻性黄疸1周组(B组)、梗阻性黄疸2周组(C组)、梗阻性黄疸1周再通1周组(D组)、梗阻性黄疸10 d再通1周组(E组)、梗阻性黄疸2周再通1周组(F组)。检测各组动物血清ALT、DBil、TBil水平;光镜下观察肝脏形态学改变;采用逆转录-聚合酶链反应(RT-PCR)法检测大鼠肝脏UCP-2mRNA的表达。结果胆道梗阻后,B、C 2组血清TBil、DBil、ALT水平较A组均升高(P值均<0.05),C组升高较B组明显(P值均<0.05)。光镜下可见B、C组肝细胞肿胀,炎性细胞浸润,汇管区伴胆管增生,C组出现典型的肝细胞片状坏死。B、C 2组肝组织UCP-2 mRNA表达较A组升高(P值均<0.05),C组升高较B组明显(P<0.05)。胆道再通组后,D、E、F 3组血清TBil、DBil、ALT水平呈不同程度下降。光镜下观察肝脏形态改变也明显趋于正常。D组肝细胞UCP-2 mRNA的表达高于B组(P<0.05),F组的表达低于C组(P<0.05),D组的表达低于E、F 2组(P值均<0.05),E、F 2组差异无统计学意义(P>0.05)。结论梗阻性黄疸时肝脏UCP-2 mRNA表达升高,随梗阻时间延长其升高趋势明显。解除梗阻时间早,则肝细胞再生活跃,UCP-2 mRNA表达暂时升高;解除梗阻时间迟,则肝组织损伤严重,再生缓慢,UCP-2 mRNA表达进行性下降,但仍高于正常。提示肝组织UCP-2 mRNA表达升高可能是梗阻性黄疸能量代谢紊乱的主要原因之一。

Objective To investigate the expression and significance of uncoupling protein 2 （UCP-2）in rats with obstructive jaundice and bile flow restoration,and to explore the molecular mechanisms of metabolic disorders and oxidative damage caused by obstructive jaundice. Methods Thirty-six healthy male Wistar rats were randomly divided into six groups：sham-operation group （group A）,obstructive jaun-dice for one week （group B）,obstructive jaundice for two weeks （group C）,obstructive jaundice for one week followed by recanalization for one week （group D）,obstructive jaundice for ten days followed by recanalization for one week （group E）,and obstructive jaundice for two weeks followed by recanalization for one week （group F）.The serum levels of alanine aminotransferase （ALT）,direct bilirubin （DBil）,and total bilirubin （TBil）were measured.Morphological changes in hepatic tissues were observed under a light microscope.Expression of UCP-2 mRNA in hepatic tissues was assessed by RT-PCR.Results After induction of obstructive jaundice,the serum levels of ALT,DBil,and TBil in groups B and C were significantly elevated compared with those in group A （P＆lt;0.05）,and group C had even higher serum levels compared with group B （P＆lt;0.05）.Hepatic tissues of group B and C displayed pathological changes,including swelling of hepatocytes,in-filtration of inflammatory cells,and bile duct hyperplasia in the portal area.Piecemeal necrosis of liver cells was observed in group C,which was accompanied by more serious pathological changes and increased proliferation of bile ducts and fibrous tissues.Compared with group A, groups B and C showed increased expression of UCP-2 mRNA in hepatic tissues （P＆lt;0.05）,and the increase was more prominent in group C （P＆lt;0.05）.After restoration of bile flow,the serum levels of ALT,DBil,and TBil in groups D,E and F decreased to varying degrees,and liver morphology tended to be normal.Expression of UCP-2 mRNA in group D was significantly higher than that in group B （P＆lt;0.05）,＆amp;nbsp;but lower than that in groups E and F （P＆lt;0.05）.Group F had significantly lower expression of UCP-2 mRNA than group C （P＆lt;0.05）. No significant difference in UCP-2 expression was observed between groups E and F （P＆gt;0.05 ）.Conclusion Expression of UCP-2 mRNA in liver is upregulated with the induction of obstructive jaundice,and the level of expression is positively correlated with the duration of obstruction.With early relief of obstruction via bile flow restoration,active regeneration of hepatic tissues occurs,leading to temporary in-crease in UCP-2 expression.However,with prolonged obstruction,extensive liver damage prevents active regeneration of hepatic tissues, which results in slightly decreased expression of UCP-2.These results indicate that upregulation of UCP-2 may be one of the major mech-anisms of metabolic disorders after obstructive jaundice.