PPARβ在虎杖苷抗高糖高胰岛素诱导心肌肥大中的作用

摘要

Aim To investigate the effect of polydatin on cardiomyocyte hypertrophy induced by high glucose (25.5 mmol·L -1 )and insulin (0.1 μmol ·L -1 ) (HGI)and its possible influence on peroxisome prolif-erator-activated receptor-β (PPARβ)/nuclear tran-scription factor-κB (NF-κB)/nitric oxide (NO)signa-ling pathway.Methods The cardiomyocyte hypertro-phy was characterized in rat primary cardiomyocytes by measuring the cell surface area,protein content,and atrial natriuretic factor (ANF)mRNA expression.The mRNA and protein expressions were measured by qRT-PCR and Western blotting,respectively.The activity of NO synthase (NOS)and NO content were measured by reagent kit through ultraviolet spectroscopy.Results HGI significantly induced cardiomyocyte hypertrophy which increased the cell surface area,protein content and ANF mRNA expression (P <0.01 ).Meanwhile, the expressions of PPARβmRNA and protein reduced while the NF-κB p65 and iNOS expressions increased significantly which occurred in parallel with rising NOS activity and NO concentration (P <0.01 ).Polydatin (0.1,1,10 μmol·L -1 )inhibited the cardiomyocyte hypertrophy induced by HGI (P <0.01 ),and re-versed the mRNA and protein expressions of PPARβ, NF-κB p65 and iNOS,and NOS activity,as well as NO content.These effects of polydatin were abolished by GSK0660 (1 μmol·L -1 ),a selective PPARβan-tagonist (P <0.05 ).Conclusion Polydatin resists HGI-induced cardiomyocyte hypertrophy,which may be mediated by PPARβup-regulation,and then NF-κB-iNOS-NO pathway inactivation.%目的：观察虎杖苷（polydatin，PD）对高糖高胰岛素[（high glucose and insulin，HGI）葡萄糖25．5 mmol·L －1＋胰岛素0.1μmol·L －1]诱导心肌肥大的影响，并探讨过氧化物酶体增殖物激活受体β（peroxisome proliferator activated receptors-β，PPARβ）、核转录因子κB （nuclear transcription factor-κB，NF-κB）及一氧化氮（nitric oxide，NO）相关信号通路在其中可能存在的作用。方法体外培养乳鼠心肌细胞，以细胞表面积、蛋白含量和心房利钠因子（atrial natriuretic factor，ANF）mRNA 表达作为心肌细胞肥大反应指标；利用qRT-PCR、Western blot 法分别检测 PPARβ、NF-κB p65及诱导型一氧化氮合酶（induced nitric oxide synthase，iNOS）mR-NA 及蛋白表达，硝酸还原酶法和分光光度法分别检测 NO含量和 NOS 活性。结果HGI 作用下，细胞表面积增大、总蛋白含量增加、ANF mRNA 表达升高（P ＜0.01），出现明显的心肌肥大；同时，PPARβ表达降低，而 NF-κB p65、iNOS 表达明显升高；总 NOS 活性及 NO 含量亦增加（P ＜0.01）。PD （0.1、1、10μmol·L －1）明显抑制 HGI 诱导的心肌细胞肥大（P ＜0.01）；并逆转 HGI 对 PPARβ及 NF-κB p65、iNOS 表达和总 NOS 活性、NO 含量的影响。PPARβ选择性阻断剂GSK0660可阻断 PD 对心肌肥大的保护，取消其上述作用（P＜0.05）。结论PD 对 HGI 诱导的心肌肥大具有保护作用，其机制可能与其上调 PPARβ表达，抑制 NF-κB-iNOS-NO信号通路激活有关。