白藜芦醇通过减缓内质网应激及增加 eNOS 的表达改善高热量高胆固醇饮食引起的内皮损伤

摘要

目的探讨白藜芦醇改善高热量高胆固醇饮食引起的血管内皮损伤的机制是否与内质网应激（endoplasmic reticu-lum stress，ERS）及内皮型一氧化氮合酶（eNOS）表达的改变有关。方法将24只♂ C57BL／6小鼠随机分为标准饮食组（SCD）、高热量高胆固醇饮食组（HCD）及高热量高胆固醇饮食＋白藜芦醇组（HCD ＋RES，白藜芦醇，400 mg·kg －1· d －1），共12周。观察胸主动脉内皮的病理学变化，检测eNOS 的表达和 ERS 上下游相关基因的表达。将血管内皮细胞（MAEC）分为正常对照组（NC 组）、模型组（棕榈酸组， PA）、中浓度 RES 药物对照组（RES）、低中高剂量 RES 治疗组（RES dose ＋PA），观察其对棕榈酸（PA）诱导的小鼠MAEC 增殖的影响，检测葡萄糖调节蛋白78（GRP78）、转录因子 GADD153（CHOP）蛋白和 eNOS 蛋白的表达。结果与 SCD 组相比，HCD 组小鼠胸主动脉管壁明显增厚，弹力纤维排列紊乱，ERS 上下游基因表达明显升高（P ＜0.05）， eNOS 蛋白表达减少；与 HCD 组相比，HCD ＋RES 组血管弹力纤维排列明显改善，ERS 相关基因的表达水平明显降低（P ＜0.05），eNOS 蛋白表达增加。与 NC 组相比，PA 组细胞增殖明显减少（P ＜0.05），GRP78和 CHOP 表达明显增加（P＜0.05），eNOS 表达降低，中、高剂量 RES 干预后 MAECs 增殖明显增强（P ＜0.05），GRP78和 CHOP 表达明显减少（P ＜0.05），eNOS 蛋白表达增加。结论白藜芦醇有明显的改善高脂饮食引起的内皮损伤和 PA 诱导的抑制内皮细胞增殖作用，可能与其减缓 ERS、增加 eNOS 的表达有关。%Aim To study whether the mechanisms in-volved in resveratrol′s protective effects on vascular en-dothelial injury induced by high-calorie and high-chol-estrol diet are concerned with ERS and the change of eNOS expression. Methods Twenty-four male C57BL/6 mice were randomly divided into standard control diet (SCD),high-calorie and high-cholestrol diet(HCD)and HCD group treated with resveratrol (HCD +RES,400 mg·kg -1 ·d -1 ,1 2 weeks).Then the thoracic aorta was separated,embedded and sliced to analyze the pathological changes by HE and resor-cinol staining.The protein distribution of eNOS was measured with immunohistochemical analysis.The up-stream and downstream genes of ERS in thoracic aorta were detected by RT-PCR.After the pretreatment with different concentrations of resveratrol,the mouse aortic endothelial cells (MAECs)were treated with palmitic acid,then the changes of cell proliferation in each group were compared.Western blot,immunofluores-cence and immunohistochemistry were used to deter-mine the protein expressions of GRP78,CHOP and eNOS respectively.Results Mice fed with HCD showed thickening of thoracic aortic wall and disorgan-ized elastic fibers as compared with those in SCD group.The mRNA levels of ERS related genes were all increased obviously (P <0.05),while the protein expression of eNOS was decreased.Compared with HCDgroup,the thickened wall and the disorganized elasticfibers were improved significantly,the mRNA levels ofERS related genes were all decreased obviously (P <0.05)and the expression of eNOS protein was increased in HCD +RES group.Compared with NCgroup, the cell proliferation was significantly decreased,meanwhile GRP78 and CHOP was significantly increased (P <0.05)and the protein expression ofeNOS was decreased in PA group.The cell proliferation was increased significantly (P <0.05),the mRNA and protein expression of GRP78 and CHOP wasobviously decreased (P <0.05),meanwhile the protein expression of eNOS was increased in the mediumand large dose of RES pretreatment groups.Conclusion Resveratrol has obvious effects of improving endothelial damages induced by HCD and decreasing cellproliferateion of MAECs induced by PA, and themechanisms are possibly related with decreased ERSand increased level of eNOS protein.