杨桃根DMDD调控JNK/P38MAPK通路抑制2型糖尿病合并非酒精性脂肪肝小鼠肝脏内质网应激

DMDD isolated from the root of Averrhoa carambola L.regulating the JNK/P38MAPK pathway to inhibit hepatic endoplasmic reticulum stress in mice with type 2 diabetes mellitus combined with non-alcoholic fatty liver disease

目的:探讨杨桃根2-十二烷基-6-甲氧基-2,5-二烯-1,4-环己二酮(DMDD)通过调控JNK/P38MAPK抑制2型糖尿病(T2DM)合并非酒精性脂肪肝(NAFLD)小鼠内质网应激的机制。方法:将C57BL/6J小鼠分为正常组、模型组、4-苯基丁酸(4-PBA)组、衣霉素(TM)组及DMDD高、中、低剂量组(DMDD_(H)组、DMDD_(M)组、DMDD_(L)组)。连续予高脂饲料喂养4周后,再一次性腹腔注射链脲佐菌素(STZ)建立T2DM合并NAFLD小鼠模型。连续给药8周后检测小鼠空腹血糖水平及肝组织丙氨酸氨基转移酶(ALT)、谷草转氨酶(AST)和血脂水平。采用苏木精—伊红(HE)染色、油红O染色观察肝组织病理学改变,western blotting法检测肝组织grp78、Chop、JNK、磷酸化(P)-JNK、P38MAPK、P-P38MAPK、Bcl-2和Bax蛋白表达。结果:与模型组相比,DMDD各剂量组空腹血糖、ALT、AST、总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)水平降低,高密度脂蛋白胆固醇(HDL-C)水平增高(P<0.05),肝组织病理损伤减轻,grp78、Chop、P-JNK、Bax和P-P38MAPK蛋白表达水平降低,Bcl-2蛋白表达水平升高(均P<0.05)。结论:杨桃根DMDD可能通过抑制JNK/P38MAPK通路减轻T2DM合并NAFLD小鼠肝脏内质网应激及肝细胞损伤和凋亡。

Objective:To explore the mechanism of 2-dodecyl-6-methoxy-2,5-diene-1,4-cyclohexanedione(DMDD)isolated from the root of Averrhoa carambola L.on the inhibition of endoplasmic reticulum stress(ERS)in mice with type 2 diabetes mellitus(T2DM)combined with non-alcoholic fatty liver disease(NAFLD)by regulating the JNK/P38MAPK pathway.Methods:The C57BL/6J mice were divided into normal group,model group,4-phenyl butyric acid(4-PBA)group,tunicamycin(TM)group,and high-,medium-,and low-dose DMDD groups(DMDDH,DMDDM,DMDDL).Streptozotocin(STZ)was injected intritoneally after 4 weeks of a continuous high-fat diet to establish a T2DM combined with the NAFLD mouse model.The fasting blood glucose(FBG)levels,alanine aminotransferase(ALT),aspartate aminotransferase(AST)and blood lipid levels in liver tissue of mice were detected after continuous administration for 8 weeks.The pathological state of the liver was observed by Hematoxylin-eosin(HE)staining and Oil Red O staining,and the expressions of grp78,Chop,JNK,phosphorylated(P)-JNK,P38MAPK,P-P38MAPK,Bcl-2 and Bax proteins in liver tissues were detected by western blotting.Results:Compared with the model group,the levels of FBG,ALT,AST,TC,TG and LDL-C in DMDD groups were reduced,the level of HDL-C increased(P<0.05),the pathological injury of liver tissue was alleviated,the protein expression levels of grp78,Chop,PJNK,Bax and P-P38MAPK decreased and the expression level of Bcl-2 protein increased(all P<0.05).Conclusion:DMDD may ameliorate endoplasmic reticulum stress,hepatocyte injury and apoptosis in mice with T2DM combined with NAFLD by inhibiting JNK/P38MAPK pathway.