水通道蛋白9在2型糖尿病大鼠肝脏中的表达变化

Expression profile of AQP9 in liver of rats with type 2 diabetes mellitus

目的探讨水通道蛋白9(Aquaporin-9,AQP9)在2型糖尿病(T2DM)鼠肝脏中的表达情况及其可能的调控机制。方法采用高脂高糖饲养联合低剂量链脲霉素诱导T2DM模型;通过HE染色法检测不同组SD大鼠肝脏的形态学改变;免疫荧光染色法观察不同组大鼠肝脏中AQP9的分布情况;Western blot检测不同组大鼠肝脏中AQP9和MAPK蛋白水平的表达变化。结果相较于对照组,HE染色显示,2型糖尿病鼠的肝脏细胞排列混乱,细胞间隙增宽,细胞水样变性显著,水肿明显,伴随大量炎性细胞浸润;免疫荧光显示,水通道蛋白9在对照组表达较少,而在糖尿病组大量表达,主要呈环形集中分布在肝细胞朝向肝血窦面的细胞膜上;Western blot分析表明,糖尿病组肝脏AQP9的表达水平明显升高(P<0.05),p-JNK/JNK的表达升高(P<0.05),p-p38/p38的表达下降(P<0.05),p-ERK/ERK的变化差异无统计学意义(P>0.05)。结论 AQP9的表达水平在T2DM鼠肝脏中显著上升,高糖环境下p38-MAPK,JNK-MAPK可能对AQP9的表达具备调控作用。

Objective To investigate the expression profile of aquaporin-9 （AQP9） in the liver of type 2 diabetes mellitus （T2DM） rats and explore the possible regulatory mechanism. Methods Male adult Sprague-Dawley rats were fed with high fat diet and given an intraperitoneal injection of streptozotocin （STZ） to induce T2DM model.Hematoxylin-eosin （HE） staining was used to observe the morphological changes in the liver.Immunofluorescence assay was employed to investigate the distribution of AQP9 in the liver.Western blotting was adopted to detect the hepatic expression of AQP9 at protein level. Results Compared with the control group, the hepatic cells in the T2DM rats were swollen, with hydropic degeneration, and in disorganized arrangement, and some inflammatory cells had infiltrated in the liver tissue.Immunofluorescent microscopy showed that AQP9 was rarely expressed in the liver of control rats, but massively expressed in the liver of T2DM rats, mainly concentrating in rings in the cell membrane towards hepatic sinusoid.Western blotting demonstrated that the expression level of AQP9 was significantly increased （P 〈 0.05）, and the ratio of p-p38 to p38 was obviously reduced （P 〈 0.05）, and that of p-JNK to JNK notably increased （P 〈 0.05）, while that of p-ERK to ERK had no change （P〉0.05）. Conclusion The expression of AQP9 is obviously increased in the liver of T2DM rats.p38-MAPK and JNK-MAPK signal pathways may play regulatory role in its expression in hyperglycemic condition.