慢性异丙肾上腺素刺激引起心肌细胞凋亡的机制研究

目的探讨异丙肾上腺素（ISO）长期刺激其受体对心肌细胞凋亡的影响。方法实验用雄性小鼠30只,分为3组,盐水对照组、ISO刺激组和ISO＋SB203580干预组,分别通过埋植渗透给药泵持续给予盐水、ISO30 mg/（kg.d）]或ISO＋p38抑制剂SB20358010 mg/（kg.d）],共7 d,随后取血清及心肌组织测定指标。结果慢性ISO刺激引起明显的心肌肥厚和细胞凋亡,增加血清和心肌中炎症因子白介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）的生成（P〈0.01）,增加诱生型一氧化氮合酶（i NOS）的表达（63%）、一氧化氮（NO）及过氧化亚硝酸盐的生成（P〈0.01）。SB203580干预后,p38激酶活性抑制,血浆和心肌中IL-6和TNF-α等炎症因子生成减少干预组与ISO组比较,IL-6：（22.26±6.38）ng/Lvs（51.32±9.20）ng/L,TNF-α：（11.75±1.09）ng/Lvs（8.64±1.01）ng/L,P〈0.01],i NOS的表达及其介导的NO生成和过氧化亚硝酸盐损伤减少干预组与ISO组比较,NO：（38.60±6.60）μmol/g蛋白vs（58.80±13.28）μmol/g蛋白;硝基酪氨酸：（2.86±0.43）μg/g蛋白vs（4.20±0.47）μg/g蛋白,P〈0.01],超氧阴离子生成也减少。结论本研究表明,慢性异丙肾上腺素刺激可以引起心肌细胞凋亡,这种致凋亡损伤可能是通过激活p38激酶,促进炎症因子生成,激活i NOS,增加自由基生成和损伤造成的。

Chronic isoproterenol stimulation induces cardiomyocyte apoptosis through p38-cytokine-iNOS pathway

Objective To explore the impact of isoproterenol（ISO） on myocardial apoptosis in mice.Methods Briefly,30 adult male mice were randomly divided into 3 groups and received continuously treatment with vehicle,ISO30 mg/（kg·d）] or ISO＋p38 inhibitor SB20358010 mg/（kg·d）]through mini-osmotic pump implanted subcutaneously for 7 days,and heart tissue and plasma were collected for further assay.Results Consistent with the previous research,chronic ISO stimulation induced markedly apoptosis.Further study indicated that ISO could induce iNOS expression（63%）,increase cytokine production（IL-6 and TNF-α）,plasma NO and heart nitrotyrosine production.SB203580 administration blocked the p38 activity thus reduced cytokine production.It also inhibited iNOS expression,decreased plasma NO and heart nitrotyrosine contentISO＋SB203580 group vs ISO group,NO：（38.60± 6.60） μmol/g protein vs（58.80± 13.28）μmol/g protein,Nitrotyrosine：（2.86±0.43）μg/g protein vs（4.20±0.47） μg/g protein,P〈0.01],reduced plasma and heart IL-6 and TNF-α levelsISO＋SB203580 group vs ISO group,IL-6：（22.26±6.38） ng/L vs（51.32±9.20） ng/L,TNF-α：（11.75±1.09） ng/L vs（8.64±1.01）ng/L,P〈0.01].Moreover,it reduced heart hypertrophy and apoptosis.Conclusion Chronic ISO stimulation can induce cardiomyocyte apoptosis.With the previous results that iNOS inhibitor 1400w also reduced cardiac hypertrophy and apoptosis while have no effect on plasma CRP increasing,ISO may exert its proapoptotic effects by p38-cytokine-iNOS-ONOO-pathway.