Urantide对动脉粥样硬化大鼠胸主动脉组织中c-Jun氨基末端激酶表达的影响及其意义

目的：探讨Urantide对动脉粥样硬化（AS）大鼠胸主动脉组织中c-Jun氨基末端激酶（JNK）mRNA和蛋白表达的影响，阐明其防治AS的分子机制。方法：采用腹腔注射维生素D₃（VitD₃）联合高脂特制饲料饲养方法建立大鼠AS模型，同时设对照组。建模成功的150只AS模型大鼠随机分为模型组、辛伐他汀组、Urantide 3 d组、Urantide 7 d组和Urantide 14 d组，每组30只。辛伐他汀组大鼠灌胃给予辛伐他汀，连续14 d；Urantide 3、7和14 d组大鼠经尾静脉注射Urantide，分别连续3、7和14 d。采用全自动生化分析仪检测大鼠血清学指标，HE染色观察大鼠胸主动脉组织病理形态表现，免疫组织化学染色、qRT-PCR和Western blotting法检测大鼠胸主动脉组织中JNK mRNA和蛋白表达水平。结果：与对照组比较，AS模型组大鼠血清中甘油三酯（TG）、总胆固醇（TC）和低密度脂蛋白（LDL）水平均升高（P<0.05），高密度脂蛋白（HDL）水平降低（P<0.05）。HE染色，模型组大鼠胸主动脉组织中泡沫细胞形成，中膜弹性纤维断裂以及钙化形成；与模型组比较，辛伐他汀组和Urantide组大鼠胸主动脉病理改变明显改善。免疫组织化学染色，对照组大鼠胸主动脉组织中JNK阳性颗粒微量表达；与对照组比较，模型组大鼠胸主动脉组织中JNK阳性表达强度明显增加（P<0.05）；与模型组比较，辛伐他汀组和不同时间Urantide组大鼠胸主动脉组织中JNK阳性表达强度明显降低（P<0.05）。qRT-PCR和Western blotting法检测，与对照组比较，模型组大鼠胸主动脉组织中JNK mRNA和蛋白表达水平明显升高（P<0.05）；与模型组比较，辛伐他汀组和不同时间Urantide组大鼠胸主动脉组织中JNK mRNA和蛋白表达水平明显降低（P<0.05）；与辛伐他汀组比较，不同时间Urantide组大鼠胸主动脉组织中JNK mRNA和蛋白表达水平进一步降低（P<0.05）。结论：Urantide可改善AS大鼠胸主动脉的病理损伤，其机制可能与抑制JNK信号通路的表达有关。

Effect of Urantide on expression of c-Jun N-terminal kinase in thoracic aorta tissue of rats with atherosclerosis and its significance

Objective:To investigate the effects of Urantide on the expressions of c-Jun N-terminal kinase (JNK) mRNA and protein in the thoracic aorta tissue of the rats with atherosclerosis (AS), and to elucidate the molecular mechanism and significance of prevention and treatment of AS. Methods:The AS rat models were established by intraperitoneal injection of Vitamin D₃ combined with high-fat diet and control group was set up at the same time. A total of 150 AS model rats were divided into model group, simvastatin group, Urantide 3 d group, Urantide 7 d group and Urantide 14 d group(n=30).The rats in simvastatin group were adminstrated with simvastatin by gavage for 14 d,and the rats in Urantide groups were injected with Urantide by caudal vein for 3,7,and 14 d. The serum markers of the rats in various groups were detected by automatic biochemical analyzer; the morphology of rat thoracic aorta tissue was observed by HE staining; the expression levels of JNK mRNA and protein in the rat thoracic aorta tissue were detected by immunohistochemical staining, qRT-PCR and Western blotting methods. Results:Compared with control group, the serum levels of triglyceride (TG), total cholesterol (TC) and low density lipoprotein (LDL) of the rats in model group were increased (P<0.05), and the level of high-density lipoprotein (HDL) was decreased (P<0.05).The HE staining results showed the formation of bubbling cells in the thoracic aorta tissue, rupture of medullary elastic fibers and calcification of the rats in model group;compared with model group, the pathological symptoms of the thoracic aorta tissue of the rats in simvastatin group and Urantide groups were improved. The immunohistochemistry results showed that the JNK positive particles were weakly expressed in the rat thoracic aorta tissue in control group; the expression intensity of JNK in the rat thoracic aorta tissue in model group was increased (P<0.05);compared with model group,the expression intensities of JNK in the rat thoracia aorta tissue in Urantide groups were significantly decreased(P<0.05). The qRT-PCR and Western blotting results showed that the expression levels of JNK mRNA and protein in the rat thoracic aorta tissue in model group were significantly increased(P<0.05) compared with control group; compared with model group,the expression levels of JNK mRNA and protein in simvastatin group and Urantide groups were gradually decreased (P<0.05);compared with simvastatin group,the expression levels of JNK mRNA and protein in the rat thoracic aorta tissue in Urantide groups were significantly decreased(P<0.05). Conclusion:Urantide can improve the pathological damage of the thoracic aorta in the AS rats, and its mechanism may be related to the inhibition of JNK signaling pathway expression.