大鼠肝移植术后肝脏损伤的动态观察及核因子E2相关因子2的作用研究

Dynamic observation of liver damage and effect of nuclear factor erythroid 2-related factor 2 in rats after liver transplantation

目的探讨大鼠肝移植术后肝脏损伤的规律以及核因子E2相关因子2(nuclear factor erythroid 2-related factor 2,Nrf2)在其中所起的作用。方法将35只雄性Sprague-Dawley(SD)大鼠随机均分为假手术组、肝移植后4h组、肝移植后8h组、肝移植后16h组、肝移植后24h组,每组7只,其中假手术组只进行开腹和血管分离,其余各组建立大鼠原位肝移植模型。术后相对应时间点处死大鼠,检测各组大鼠肝脏病理学改变,氧化损伤和抗氧化物的含量变化,分析大鼠肝移植术后肝脏损伤的规律及特点。同时检验移植肝Nrf2蛋白的表达变化。结果肝移植术后8h,大鼠移植肝损伤最为明显,过氧化氢、羟自由基和丙二醛的含量明显升高,而抗氧化物超氧化物歧化酶、过氧化氢酶、还原型谷胱甘肽的含量显著下降。随后,活性氧水平和抗氧化物活性逐渐恢复至正常水平,肝脏损伤逐渐修复。肝移植术后大鼠肝组织Nrf2蛋白的表达从术后4h即开始明显升高,肝移植术后8、16、24h肝组织Nrf2蛋白的表达均明显高于假手术组。结论大鼠肝移植术后8h肝脏损伤最为明显,而后逐渐恢复。移植肝的损伤程度与活性氧水平以及抗氧化物活性的下降趋势高度一致。而这一变化过程可能与Nrf2的高表达上调了抗氧化物的含量密切相关。

Objective To investigate the pattern of liver damage and the effect of nuclear factor erythroid 2-related factor 2 （Nrf2） in rats after liver transplantation （LT）. Methods Thirty-five male Sprague-Dawley （SD） rats were divided into 5 groups： the sham group, and 4, 8, 16, 24 h after LT groups （7 rats in each group）. Rats in the sham group only underwent laparotomy and vascular separation, while in other groups all the rats were performed the model of orthotopic liver transplantation. The rats were executed at the relative time after the operation. Liver pathological changes, oxidative damage and antioxidant changes were detected to analyze the pattern and feature of liver damage in rats after LT. And the Nrf2 expression of transplanted liver was also detected. Results Liver damage was most serious at 8 h after LT. The levels of hydrogen peroxide （ H2 02 ）, hydroxyl radical （. OH） and malonaldehyde （MDA） increased obviously while the antioxidant contents such as superoxide dismutase （SOD）, catalase （CAT）, and glutathione （GSH） decreased. Then the reactive oxygen species （ROS） level and the antioxidant activities returned to normal gradually and the liver damage began to alleviate and recover. The Nrf2 expression in liver tissues of rats increased evidently 4 h after LT. The Nrf2 expressions in 8, 16, 24 h after LT groups were all higher than thatin the sham group. Conclusions Liver damage is most serious at 8 h after LT and then alleviate gradually. The degree of liver damage is highly consistent with the decline trend of ROS level and antioxidant activities. The change may be closely related with the high expression of Nrf2 which up-regulates the antioxidant level.