基于GSK-3β/Fyn/Nrf2信号通路探讨槲皮素对自发性高血压大鼠心肌纤维化的影响及内在机制

Effects of Quercetin on Myocardial Fibrosis in Spontaneously Hypertensive Rats and Its Underlying Mechanism Based on GSK-3β/Fyn/Nrf2 Signaling Pathway

目的:探究槲皮素在自发性高血压大鼠(SHR)心肌纤维化中的作用机制。方法:50只SHR随机分为SHR组、卡托普利组、槲皮素低、中、高剂量组,每组10只;10只Wky大鼠为Wky组。卡托普利组灌胃给予卡托普利30 mg/kg,槲皮素低、中、高剂量组分别灌胃给予槲皮素20、50、100 mg/kg,Wky组、SHR组给予等量0.9%氯化钠溶液,每天1次,连续12周。尾袖法每2周测定大鼠尾动脉收缩压(SBP);给药结束,称定心脏质量,大鼠处死,称定其左心室质量(LVM),计算左心室肥厚指数(LVMI);比色法测血清超氧化物歧化酶(SOD)、总抗氧化能力(T-AOC)活性、丙二醛(MDA)含量;实时荧光定量-聚合酶链式反应法和Western blot法检测左心室组织中糖原合成酶激酶-3β(GSK-3β)、非受体酪氨酸激酶Fyn、核因子相关因子2(Nrf2)的mRNA、蛋白表达,以及Ⅰ型、Ⅲ型胶原(Collagen-Ⅰ、Collagen-Ⅲ)蛋白表达。结果:与Wky组比较,SHR组大鼠SBP、心脏质量、LVMI显著升高(P<0.01);血清SOD、T-AOC活性显著降低,MDA含量显著增加(P<0.01);左心室Collagen-Ⅰ、Collagen-Ⅲ表达显著升高(P<0.01),Nrf2、GSK-3β的mRNA、蛋白表达显著降低(P<0.01),Fyn的mRNA、蛋白表达显著升高(P<0.01)。与SHR组比较,卡托普利组、槲皮素低、中、高剂量组大鼠SBP、心脏质量、LVM、LVMI均显著降低(P<0.01);血清SOD、T-AOC活性显著升高,MDA含量显著降低(P<0.05,P<0.01);槲皮素中、高剂量组左心室中Collagen-Ⅰ、Collagen-Ⅲ蛋白表达显著降低(P<0.01);槲皮素低、中、高剂量组左心室中Nrf2、GSK-3βmRNA、蛋白表达显著升高,Fyn mRNA、蛋白表达显著降低(P<0.05,P<0.01)。结论:槲皮素可抑制SHR心肌纤维化,其机制可能是通过下调GSK-3β/Fyn信号通路,激活Nrf2诱导的抗氧化通路,减少SHR心肌组织氧化应激反应。

Objective:To explore the mechanism of quercetin in myocardial fibrosis in spontaneously hypertensive rats(SHR).Methods:Fifty SHRs were randomly divided into SHR group,Captopril group,low-,medium-,and high-dose of quercetin groups,with 10 in each group.Ten Wky rats were included in the Wky group.Captopril group was given Captopril 30 mg/kg by gavage,quercetin low-,medium-,and high-dose groups were given quercetin 20,50,and 100 mg/kg by gavage,respectively.Wky group and SHR groups were given equal amounts of 0.9%sodium chloride solution once a day for 12 consecutive weeks.The systolic blood pressure(SBP)of the rat tail artery was measured every 2 weeks using the tail cuff method.After administration,weigh the heart mass,and the rats were killed.Measure their left ventricular mass(LVM),and calculate the left ventricular mass index(LVMI),serum superoxide dismutase(SOD),total antioxidant capacity(T-AOC)activity,and malondialdehyde(MDA)content were measured by colorimetry.mRNA and protein expressions of glycogen synthase kinase 3β(GSK-3β)in left ventricular tissue and non-receptor tyrosine kinase Fyn,nuclear factor E2-related factor 2(Nrf2),and protein expressions of collagen typeⅠandⅢ(Collagen-Ⅰand Collagen-Ⅲ)were detected by real-time fluorescence quantification-polymerase chain neaction(RT-PCR)and Western blot.Results:Compared with Wky group,SBP,heart mass,and LVMI in SHR group were significantly increased(P<0.01).The activities of SOD and T-AOC in serum were significantly decreased,while the content of MDA was significantly increased(P<0.01).The expressions of Collagen-Ⅰand Collagen-Ⅲin left ventricle were significantly increased(P<0.01).The mRNA and protein expressions of Nrf2 and GSK-3βwere significantly decreased(P<0.01),while the mRNA and protein expressions of Fyn were significantly increased(P<0.01).Compared with SHR group,the SBP,heart mass,LVM,and LVMI of rats in Captopril group,quercetin low-,medium-,and high-dose groups were significantly decreased(P<0.01).The activities of SOD and T-AOC in serum were significantly increased,while the content of MDA was significantly decreased(P<0.05,P<0.01).The protein expressions of Collagen-Ⅰand Collagen-Ⅲin the left ventricle of the medium-and high-dose quercetin groups were significantlys decreased(P<0.01).The mRNA and protein expressions of Nrf2,GSK-3βin left ventricle of quercetin low-,medium-,and high-dose groups were significantly increased,while the mRNA and protein expressions of Fyn were significantly decreased(P<0.05,P<0.01).Conclusion:Quercetin can inhibit myocardial fibrosis in SHR,and its mechanism may be through down-regulating GSK-3β/Fyn signaling pathway,activates Nrf2-induced antioxidant pathway and reduces oxidative stress response in SHR myocardial tissue.