摘要目的 探讨多巴酚丁胺选择性预激动β1肾上腺素受体对大鼠心肌缺血再灌注损伤中高迁移率族蛋白-1(HMGB1)表达的影响及其机制.方法 健康雄性Sprague-Dawley (SD)大鼠分为假手术组、缺血再灌注组(I/R组)、低剂量多巴酚丁胺(5μg·kg-1·min-1)预处理组(低剂量多巴酚丁胺组)、高剂量多巴酚丁胺(10 μg·kg-1· min-1)预处理组(高剂量多巴酚丁胺组)、LY294002[0.3mg/kg,磷脂酰肌醇3-激酶(PI3K)抑制剂]+高剂量多巴酚丁胺(10 μg·kg-1·min-1)预处理组(LY294002组)、SB203580[1 mg/kg,p38丝裂原活化蛋白激酶(p38 MAPK)抑制剂]+高剂量多巴酚丁胺(10 μg·kg-1·min-1)预处理组(SB203580组)和锌原卟啉Ⅸ(ZnPPⅨ,10 mg/kg,HO-1抑制剂)+高剂量多巴酚丁胺(10 μg·kg-1·min-)预处理组(ZnPPⅨ组),共7组,每组12只.分别采用生理盐水、多巴酚丁胺、LY294002、SB203580、ZnPPⅨ预处理各组大鼠后,建立大鼠心肌缺血再灌注(L/R)模型.检测各组大鼠的心肌梗死范围,心肌酶[包括肌酸激酶(CK)、乳酸脱氢酶(LDH)],炎症因子[肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)],氧化应激指标[包括丙二醛(MDA)、超氧化物歧化酶(SOD)],血红素加氧酶-1(HO-1)、核因子-κB(NF-κB)以及HMGB1蛋白表达的变化.结果(1)低剂量和高剂量多巴酚丁胺预处理组中大鼠心肌梗死面积均显著低于I/R组[(34.13±1.90)％和(28.50±1.30)％比(51.25±1.50)％,P均＜0.05].而LY294002组、SB203580组和ZnPPⅨ组中大鼠心肌梗死面积则均显著大于低剂量和高剂量多巴酚丁胺组(P均＜0.05).(2) I/R组大鼠中血清LDH和CK的活性均显著高于假手术组(P均＜0.05).低剂量和高剂量多巴酚丁胺组大鼠血清中LDH和CK的活性则均显著低于I/R组(P均＜0.05).而LY294002组、SB203580组和ZnPPⅨ组大鼠血清中LDH和CK活性则均显著高于多巴酚丁胺低剂量和高剂量组(P均＜0.05).(3) I/R组大鼠心肌组织中TNF-α和IL-6的含量均显著高于假手术组(P均＜0.05).低剂量和高剂量多巴酚丁胺组大鼠心肌组织中TNF-α和IL-6的含量则均显著低于与I/R组(P均＜0.05).而LY294002组、SB203580组和ZnPPⅨ组大鼠心肌组织中TNF-α和IL-6含量则均显著高于低剂量和高剂量多巴酚丁胺组(P均＜0.05).(4)I/R组大鼠心肌组织中MDA的含量显著高于假手术组,SOD的活性则显著低于假手术组(P均＜0.05).低剂量和高剂量多巴酚丁胺组大鼠心肌组织中MDA的含量则均显著低于I/R组(P均＜0.05),SOD活性则均显著高于I/R组(P均＜0.05).而LY294002组、SB203580组和ZnPPⅨ组大鼠心肌组织中MDA的含量则均显著高于低剂量和高剂量多巴酚丁胺组,SOD的活性则均显著低于低剂量和高剂量多巴酚丁胺组(P均＜0.05).(5)I/R组大鼠心肌组织中HO-1、NF-κB和HMGB1蛋白的表达水平均显著高于假手术组(P均＜0.05).低剂量和高剂量多巴酚丁胺预组大鼠心肌组织中HO-1蛋白的表达水平均显著高于I/R组(P均＜0.05),而NF-κB和HMGB1的蛋白表达水平则均显著低于I/R组(P均＜0.05).而LY294002组、SB203580组和ZnPPⅨ组大鼠心肌组织中HO-1的表达水平则均显著低于低剂量和高剂量多巴酚丁胺组(P均＜0.05),NF-κB和HMGB1的蛋白表达水平则均显著高于低剂量和高剂量多巴酚丁胺组(P均＜0.05).结论选择性预激动β1肾上腺素能受体可显著抑制HMGB1释放,从而对心肌缺血再灌注损伤产生保护作用.其作用机制可能与通过PI3K/p38 MAPK信号通路诱导HO-1表达有关.

abstractsObjective To investigate whether selectively stimulating β1-adrenergic receptor could inhibit high mobility group box 1 protein and attenuate myocardial ischemia/reperfusion (I/R) injury in rats.Methods Eighty healthy male Sprague-Dawley (SD) rats were randomly divided into seven groups:(1) Sham operated group (SO) ; (2) Ischemia/reperfusion (I/R) group; (3) Dobutamine1 (5 μg · kg-1· min-1) +I/R group; (4) Dobutamine2 (10 μg · kg-1 · min-1) + I/R group; (5) LY294002 (0.3mg/kg) + Dobutamine2 + I/R group; (6) SB203580 (1 mg/kg) + Dobutamine2 + I/R group; (7) ZnPPⅨ (10 mg/kg) + Dobutamine2 + I/R group.Rats were pretreated by saline,dobutamine,LY294002,SB203580 and ZnPPⅨ,respectively,then underwent myocardial I/R.Myocardial I/R injury and oxidative stress were assessed,and myocardial HO-1,NF-κB and HMGB1 expressions were measured by Western blot analysis.Results Dobutamine significantly reduced the myocardial infarct size (P ＜ 0.05),myocardial enzymes (LDH and CK) (P ＜ 0.05) and proinfiammation cytokines (TNF-α and IL-6),reduced oxidative stress (MDA and SOD) in a dose-dependent manner (all P ＜ 0.05).Meanwhile,dobutamine significantly and dose-dependently mediated the induction of HO-1 (P ＜ 0.05),the expression of NF-κB (P ＜ 0.05) and HMGB1 (P ＜ 0.05).However,all the effects could be significantly reversed by co-treatment with LY294002,SB203580 and ZnPP Ⅸ (all P ＜ 0.05).Conclusions Current study demonstrates that selectively stimulating β1-adrenergic receptor by dobutasmine could reduce rat myocardial I/R injury in vivo through promoting the induction of HO-1 and inhibiting HMGB1 release.