毛兰素通过JNK/c-Jun信号通路对2型糖尿病大鼠肝脏损伤的保护作用机制研究

Study on the protective mechanism of Erianin on liver injury in type 2 diabetic rats through the JNK/c-Jun signaling pathway

目的基于c-Jun氨基末端激酶(JNK)/c-Jun信号通路对氧化应激反应的调控作用,研究毛兰素对2型糖尿病大鼠肝脏损伤的保护作用。方法于2021年10月至2022年2月腹腔注射链脲佐菌素构建糖尿病大鼠模型,将造模成功大鼠分为模型组、毛兰素低剂量组(10 mg/kg)、毛兰素高剂量组(40 mg/kg),及罗格列酮组(1.25 mg/kg)、毛兰素(40 mg/kg)+JNK激活组(5 mg/kg),每组10只,另取正常饲养大鼠10只作为对照组。连续给药6周后,通过血糖仪和胰岛素放射免疫分析试剂盒检测空腹血糖(FBG)、空腹胰岛素(FINS)水平,计算胰岛素抵抗指数(HOMA-IR)及胰岛素敏感指数(ISI);天平称取大鼠体质量和肝质量,计算肝脏指数;试剂盒检测丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量;HE染色观察肝脏组织病理学变化;western blotting法检测肝脏组织中JNK/c-Jun信号通路相关蛋白表达。结果与对照组相比,模型组肝脏指数[(4.26±0.12)g/100 g比(2.24±0.09)g/100 g]、FBG[(21.49±1.78)mmol/L比(5.14±0.45)mmol/L]、FINS[(80.17±6.38)mmol/L比(22.35±2.04)mmol/L]、HOMA-IR[(76.46±6.56)比(5.11±1.12)]、ALT[(138.71±10.21)U/L比(70.29±5.54)U/L]和AST活性[(77.21±5.08)U/L比(40.38±3.27)U/L]、MDA含量[(13.45±1.34)nmol/mg prot比(3.72±0.87)nmol/mg prot]、JNK/c-Jun信号通路相关蛋白表达均明显升高(P<0.05),体质量、ISI[(−7.45±0.18)比(−4.74±0.11)]、SOD[(100.79±11.22)U/mg prot比(223.46±19.86)U/mg prot]和GSH-Px活性[(24.42±1.74)U/mg prot比(56.79±3.18)U/mg prot]明显降低(P<0.05),且肝脏组织病理损伤较为严重;与模型组相比,毛兰素低剂量组、毛兰素高剂量组和罗格列酮组肝脏指数、FBG、FINS、HOMA-IR、ALT和AST活性、MDA含量、JNK/c-Jun信号通路相关蛋白表达均明显降低(P<0.05),体质量、ISI、SOD和GSH-Px活性明显升高(P<0.05),减轻肝脏损伤程度;与毛兰素高剂量组相比,毛兰素低剂量组、毛兰素+JNK激活组肝脏指数、FBG、FINS、HOMA-IR、ALT和AST活性、MDA含量、JNK/c-Jun信号通路相关蛋白表达均明显升高(P<0.05),体质量、ISI、SOD和GSH-Px活性明显降低(P<0.05),肝脏损伤恢复缓慢。结论毛兰素可通过调控JNK/c-Jun信号通路,抑制JNK/c-Jun通路蛋白表达,从而缓解氧化应激反应,改善糖尿病大鼠肝脏损伤。

Objective Based on the regulatory effect of the c-Jun N-terminal kinase(JNK)/c-Jun signaling pathway on the oxidative stress response,we studied the protective effect of Erianin on liver injury in type 2 diabetic rats.Methods The diabetic rat model was constructed by intraperitoneal injection of streptozotocin from October 2021 to February 2022,and the successfully modeled rats were divided into the model group,Erianin low-dose group(10 mg/kg),Erianin high-dose group(40 mg/kg),rosiglitazone group(1.25 mg/kg),and Erianin(40 mg/kg)+JNK activator(5 mg/kg)group,with 10 rats in each group.After 6 weeks of continuous administration,the levels of fasting blood glucose(FBG)and fasting insulin(FINS)were detected by a glucose meter and insulin radioimmunoassay kit,and the insulin resistance index(HOMA-IR)and insulin sensitivity index(ISI)were calculated;the body weight and liver weight of rats were weighed with a balance,and the liver index was calculated;the kit was used to detect the contents of alanine aminotransferase(ALT),aspartate aminotransferase(AST),total superoxide dismutase(T-SOD),glutathione peroxidase(GSH-Px)and malondialdehyde(MDA).HE staining was used to observe the pathological changes in the liver.Western Blotting was used to detect the expression of JNK/c-Jun signaling pathway-related proteins in liver tissues.Results Compared with the control group,the liver index[(4.26±0.12)g/100 g vs.(2.24±0.09)g/100 g],FBG[(21.49±1.78)mmol/L vs.(5.14±0.45)mmol/L],FINS[(80.17±6.38)mmol/L vs.(22.35±2.04)mmol/L],HOMA-IR[(76.46±6.56)vs.(5.11±1.12)],ALT[(138.71±10.21)U/L vs.(70.29±5.54)U/L]and AST activity[(77.21±5.08)U/L vs.(40.38±3.27)U/L],and MDA content[(13.45±1.34)nmol/mg prot vs.(3.72±0.87)nmol/mg prot],and JNK/c-Jun signaling pathway-related protein expression in the model group were significantly higher(P<0.05),the body weight,ISI[(−7.45±0.18)vs.(−4.74±0.11)],SOD[(100.79±11.22)U/mg prot vs.(223.46±19.86)U/mg prot]and GSH-Px activity[(24.42±1.74)U/mg prot vs.(56.79±3.18)U/mg prot]were significantly lower(P<0.05),and liver tissue pathological damage was more severe.Compared with the model group,the liver index,FBG,FINS,HOMA-IR,ALT and AST activities,MDA content,and JNK/c-Jun signaling pathway-related protein expression in the Erianin low-dose group,Erianin high-dose group,and rosiglitazone group were significantly lower(P<0.05),and the body weight,ISI,SOD and GSH-Px activities were significantly higher(P<0.05),reducing the degree of liver injury.Compared with the Erianin high-dose group,the liver index,FBG,FINS,HOMA-IR,ALT and AST activities,MDA content,and JNK/c-Jun signaling pathway-related protein expression in the Erianin low dose group and Erianin+JNK activator group were significantly higher(P<0.05),the body weight,ISI,SOD and GSH-Px activities were significantly lower(P<0.05),and slow recovery from liver injury was observed.Conclusion Erianin ameliorates oxidative stress and improves liver injury in diabetic rats by regulating the JNK/c-Jun signaling pathway and inhibiting the JNK/c-Jun pathway protein expression.