老年大鼠肝脏解偶联蛋白2表达与衰老关系的研究

Research on Relationship Between Expression of UCP_2 in Livers of Old-aged Rats and Aging

目的探讨解偶联蛋白2(uncoupling protein 2,UCP2)在老年大鼠肝脏组织中的表达及其与衰老的关系。方法健康雄性SD大鼠30只,按年龄分为新生组、成年组和老年组,实验室适应性喂养7 d后断头处死,分别取各组大鼠肝组织测定丙二醛(malondialdehyde,MDA)、谷胱甘肽(glutathione,GSH)、三磷酸腺苷(adenosine triphosphate,ATP)的含量;通过免疫组织化学观察肝组织中UCP2蛋白的表达与分布,Western blot方法检测肝细胞线粒体内UCP2蛋白的表达并进行定量分析。结果老年组大鼠肝组织中MDA含量高于幼年组和成年组(P<0.01);老年组大鼠肝组织GSH含量显著低于幼年组和成年组(P<0.01);老年组的ATP水平比幼年组和成年组水平显著降低(P<0.01);老年组UCP2表达高于幼年组和成年组(P<0.01)。结论老年大鼠肝MDA含量升高、GSH含量下降,提示老年大鼠肝内活性氧(re-active oxygen species,ROS)水平较高,并引起UCP2表达增多,UCP2可能对延缓肝细胞的衰老起重要作用;UCP2的高表达可能是老年大鼠肝组织ATP下降的原因之一;肝组织UCP2表达水平主要受ROS水平的调节,但ATP水平不仅受到UCP2的调节,还受细胞的代谢状态的影响。

Objective To discuss the relationship between the expression of UCP2 in the livers of oldaged rats and aging. Methods Thirty healthy male SD rats were chosen and divided into three groups： young group, adult group and old - aged group. They were fed for 7 days and then killed by cutting heads. These rats＇ hepatic tissue was taken out respectively to test the contents of malondialdehyde（MDA）, glutathione（GSH） and andadenosine triphosphate（ATP） ; and UCP2 expression was tested by chemical coloration in western blot method. These figures were then used to make quantitative analysis. Results The MDA content of old - aged group increased significantly as compared with the young group and adult group （P〈 0.01）. The GSH content of old-aged group went down compared with the young group and adult group （P〈 0.01 ）. The ATP level of oldaged group decreased significantly compared with the young group and adult group （P〈 0.01 ）. The UCP2 in parenchymal cells in the livers of old- aged group expressed the most, the expression of UCP2 in young group is less, its expression in the adult group is the lest. It showed that the average relative photodensity was significantly increased in old - aged group compared with the young group and adult group （P〈 0.01 ）. Conclusions The content of MDA rises, while the content of GSH descends in the livers of old -aged rats. The results suggest that the level of ROSis relatively higher and causes the increase of UCP2 expression. UCP2 may perform important function in staving off the ageing of liver cells. The higher expression of UCP2 may be one of the reasons of the decrease of ATP in old- aged rats. The expression of UCP2 in hepatic tissue is mainly regulated by the content of ROS. The level of ATP is not only regulated by UCP2 but also influenced by the metabolic state of cells.