【摘要】 目的:研究雌二醇(E2)通过雌激素受体β(ERβ)介导细胞外调节蛋白激酶(ERK)通路激活减轻心肌缺血/再灌注(I/R)损伤的作用及机制。方法:84只成年雌性SD大鼠进行去卵巢手术并随机分为：对照组、NC-siRNA腺相关病毒(AAV)组进行假手术，I/R组、E2+I/R组、NC-siRNA AAV+I/R组、NC-siRNA AAV+E2+I/R组、ERβ-siRNA AAV+E2+I/R组。采用冠状动脉左前降支结扎的方法制备心肌I/R损伤模型，E2+I/R组、NC-siRNA AAV+E2+I/R组、ERβ-siRNA AAV+E2+I/R组造模前给予E2灌胃、连续60 d, NC-siRNA AAV+I/R组、NC-siRNA AAV+E2+I/R组、ERβ-siRNA AAV+E2+I/R组造模前24 h给予相应AAV尾静脉注射。再灌注120 min后，检测血清乳酸脱氢酶(LDH)、磷酸肌酸激酶(CK)、磷酸肌酸激酶同工酶(CK-MB)含量，心肌梗死面积，心肌中ERβ、p-ERK表达水平及肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)、丙二醛(MDA)、总抗氧化力(T-AOC)的含量。结果:I/R组的血清LDH、CK、CK-MB含量、心肌梗死面积及心肌中TNF-α、IL-1β、MDA的含量均高于对照组，心肌中ERβ、p-ERK的表达水平及T-AOC的含量均低于对照组(P<0.05);E2+I/R组的血清LDH、CK、CK-MB含量、心肌梗死面积及心肌中TNF-α、IL-1β、MDA的含量均低于I/R组，心肌中ERβ、p-ERK的表达水平及T-AOC的含量均高于I/R组(P<0.05);尾静脉注射ERβ-siRNA AAV敲低ERβ的表达后，ERβ-siRNA AAV+E2+I/R组的血清LDH、CK、CK-MB含量、心肌梗死面积及心肌中TNF-α、IL-1β、MDA的含量均高于NC-siRNA AAV+E2+I/R组，心肌中ERβ、p-ERK的表达水平及T-AOC的含量均低于NC-siRNA AAV+E2+I/R组(P<0.05)。结论:雌二醇对去卵巢大鼠心肌I/R损伤具有保护作用，该作用与促进ERβ介导ERK通路激活、减轻炎症反应及氧化应激反应有关。更多还原

【Abstract】 Objective: To study the effects of estradiol(E2) on alleviating myocardial ischemia/reperfusion(I/R) injury through estrogen receptorβ(ERβ) mediated extracellular regulated protein kinases(ERK) pathway activation. Methods: Eighty-four adult female SD rats were ovariectomized and randomly divided into control group, NC siRNA adeno-associated virus(AAV) group received sham operation, the myocardial I/R injury model was prepared by ligation of the left anterior descending coronary artery in I/R group, E2+I/R group, NC siRNA AAV+I/R group, NC siRNA AAV+E2+I/R group and ERβ-siRNA AAV+E2+I/R group. E2+I/R group, NC siRNA AAV+E2+I/R group and ERβ-siRNA AAV+E2+I/R group were treated with E2 0.8 mg/kg by gavage for 60 days before modeling. NC siRNA AAV+I/R group, NC siRNA AAV+E2+I/R group, and ERβ-siRNA AAV+E2+I/R group were treated with AAV by caudal vein injection 24 h before modeling. After 120 min of reperfusion, the contents of serum lactate dehydrogenase(LDH), phosphocreatine kinase(CK), phosphocreatine kinase isoenzyme(CK-MB), myocardial infarction area and the expressions of ERβ, p-ERK, the contents of tumor necrosis factor-α(TNF-α), interleukin-1β(IL-1 β), malondialdehyde(MDA) and total antioxidant capacity(T-AOC) in myocardium were measured. Results: The contents of serum LDH, CK, CK-MB, myocardial infarction area and the contents of TNF-α, IL-1 β, MDA in myocardium of I/R group were higher than those of the control group, the expression levels of ERβ and p-ERK and the content of T-AOC were lower than those in the control group(P<0.05). The contents of serum LDH, CK and CK-MB, myocardial infarction area and the contents of TNF-α, IL-1 β and MDA in myocardium of E2+I/R group were lower than those of the I/R group, the expression levels of ERβ and p-ERK and the content of T-AOC were higher than those of the I/R group(P<0.05). After knockdown ERβ by caudal vein injection of ERβ-siRNA AAV, the contents of serum LDH, CK and CK-MB, myocardial infarction area and the contents of TNF-α, IL-1 β and MDA in myocardium of ERβ-siRNA AAV+E2+I/R group were higher than those of NC-siRNA AAV+E2+I/R, the expression levels of ERβ and p-ERK and the content of T-AOC were lower than those of NC-siRNA AAV+E2+I/R(P<0.05). Conclusion: E2 has protective effects on myocardial I/R injury in ovariectomized rats, which are related to the promotion of ERβ mediating the activation of ERK pathway, reducing inflammatory and oxidative stress responses.更多还原