梓醇对T2DM大鼠大血管病变的保护作用及与oxLDL/LDL和NF-κB信号通路的关系

The protective effect of catalpol on vascular lesions of T2DM rats and the involvement of the oxLDL/LDL and NF-κB signaling pathway

目的探讨梓醇对2型糖尿病(T2DM)大鼠大血管病变的保护作用与氧化低密度脂蛋白(oxLDL)/低密度脂蛋白(LDL)和核转录因子-κB(NF-κB)信号通路的关系。方法用高糖高脂饲料喂养和腹腔注射STZ复合因素对大鼠进行T2DM造模,将大鼠分为模型组、二甲双胍组(134 mg·kg^(-1)·d^(-1))、梓醇组(10 mg·kg^(-1)·d^(-1)),另设对照组,每组10只,模型组和对照组给予相同体积的0.9%氯化钠溶液,干预4周。结束后,自动生化分析仪检测大鼠血清总胆固醇(TC)、三酰甘油(TG)、空腹血糖(FBG)、低密度脂蛋白(LDL)和高密度脂蛋白(HDL)水平;酶联免疫吸附法测定人巨噬细胞趋化蛋白-1(MCP-1)、oxLDL含量;RT-PCR法检测主动脉壁LOX-1、NF-κB p65、MCP-1 mRNA表达;Western blot检测主动脉壁LOX-1、NF-κB p65、MCP-1蛋白表达;透射电镜观察大鼠主动脉内皮细胞结构。结果对照组大鼠主动脉内皮细胞形态正常,模型组细胞显著肿胀,连续性中断、见空泡,部分内皮细胞有显著脱落,细胞核褶皱变形,线粒体、内质网中度肿胀,嵴肿胀紊乱或溶解,见脂滴、糖原颗粒;二甲双胍组和梓醇组内皮细胞形态结构轻微肿胀,线粒体、内质网结构正常,细胞核轻微变形,部分内皮细胞有轻微脱落,损伤程度显著轻于模型组。与对照组比较,模型组血清FBG、TC、TG、LDL水平,MCP-1和oxLDL水平,主动脉壁LOX-1、NF-κB p65、MCP-1 mRNA及蛋白表达量显著性升高(P<0.05);与模型组比较,二甲双胍组和梓醇组血清FBG、TC、TG、LDL水平,MCP-1和oxLDL水平,主动脉壁LOX-1、NF-κB p65、MCP-1 mRNA及蛋白表达量显著性降低(P<0.05)。结论梓醇可能通过oxLDL/LDL和NF-κB信号通路减轻T2DM大鼠大血管病变。

Objective To investigate the protective effect of catalpol on vascular lesions of type 2 diabetes mellitus(T2DM)rats and the involvement of the oxidized low density lipoprotein(oxLDL)/low density lipoprotein(LDL)and nuclear transcription factor-κB(NF-κB)signaling pathway.Methods A rat T2DM model was created by feeding a high-sugar and high-fat diet and intraperitoneal injection of streptozotocin(STZ).The rats were randomly grouped into blank control group,model group,metformin group(134 mg·kg^(-1)·d^(-1)),catalpol group(10 mg·kg^(-1)·d^(-1)),with 10 in each group.Rats in the model group and blank control group were given the same volume of normal saline for 4 weeks.Serum total cholesterol(TC),triacylglycerol(TG),fasting blood glucose(FBG),low-density lipoprotein(LDL)and high-density lipoprotein(HDL)were measured by automatic biochemical analyzer.The contents of human macrophage chemoattractant protein-1(MCP-1)and oxLDL were determined by enzyme-linked immunosorbent assay(ELISA).The real-time reverse transcription polymerase chain reaction(RT-PCR)and Western blot applied to detect the mRNA and protein expressions of lectin-like oxidized low-density lipoprotein receptor-1(LOX-1),NF-κB p65 and MCP-1 in rat aortic wall,respectively.The structure of rat aortic endothelial cells was observed by transmission electron microscopy(TEM).Results The morphology of aortic endothelial cells in the blank control group was normal,which,in the model group,were obviously swollen,with continuous interruption and vacuoles.Some endothelial cells in the model group were obviously exfoliated,with folded and deformed nuclei,moderately swollen mitochondria and endoplasmic reticulum,swollen,disordered or dissolved cristae,and presence of lipid droplets and glycogen granules.The morphology and structure of endothelial cells in metformin group and catalpol group were slightly swollen,and the structure of mitochondria and endoplasmic reticulum was normal,with slightly deformed nucleus,some slightly shed endothelial cells,and significantly milder degree of injury.Compared with those of the control group,serum FBG,TC,TG,and LDL levels,contents of MCP-1 and oxLDL,and mRNA and protein expressions of LOX-1,NF-κB p65,and MCP-1 in the aortic wall were significantly higher in the model group(P<0.05),which,in the metformin group and catalpol group were significantly lower than those of model group(P<0.05).Conclusion Catalpol may alleviate the vascular lesion of T2DM rats through the oxLDL/LDL and NF-κB signaling pathway.