Tribble 3在糖尿病心肌病心肌间质重构时的表达和缬沙坦干预的影响

目的探讨Tribble3(TRB3)基因在大鼠Ⅱ型糖尿病心肌病心肌间质重构中的可能作用及缬沙坦干预的影响。方法32只Wistar大鼠以高脂高热量饮食诱导加小剂量链脲佐菌素注射建立Ⅱ型糖尿病心肌病动物模型,随机分为糖尿病心肌病组和缬沙坦治疗组(缬沙坦30mg·kg-1·d-1灌胃),以8只正常大鼠作对照。采用Masson染色测定心肌胶原含量,实时定量逆转录-聚合酶链反应检测心肌TRB3mRNA表达。结果与对照组比较,糖尿病心肌病组左室心肌组织胶原含量显著高(11·01±3·05比16·92±3·18,P<0·01),与糖尿病心肌病组相比,缬沙坦组心肌胶原含量明显低(16·92±3·18比13·23±3·14,P<0·05),心肌组织胶原含量与空腹血糖呈明显正相关(r=0·746,P<0·01);与对照组相比,糖尿病心肌病组大鼠心肌TRB3mRNA表达水平明显高(0·0198±0·0082比0·1108±0·0933,P<0·05);与糖尿病心肌病组比较,缬沙坦组TRB3mRNA表达水平明显低(0·1108±0·0933比0·0367±0·0234,P<0·05);与对照组比较,缬沙坦组TRB3mRNA表达水平差异无统计学意义(P>0·05);糖尿病心肌病组大鼠心肌TRB3mRNA表达与血糖正相关(r=0·69,P<0·05),与心肌组织胶原含量正相关(r=0·67,P<0·05)。结论首次证实TRB3基因在大鼠心肌中表达,发现了TRB3基因可能参与了糖尿病心肌病心肌间质重构,缬沙坦干预减轻糖尿病心肌病心肌间质重构,改善左室舒张和收缩功能,下调TRB基因的表达。

Effect of valsartan on Tribble 3 gene expression in rats with experimental diabetic cardiomyopathy

OBJECTIVE: Tribbles, a protein family controlling mitogen-activated protein kinase cascades, might contribute to the remodeling process in dilated cardiomyopathy. We investigated the gene expression of Tribble 3 (TRB(3)), cardiac function and collagen changes in rats with diabetic cardiomyopathy (DCM) and the modulating effects of valsartan on them. METHODS: Male Wistar rats were fed with high cholesterol diet throughout the study period, streptozocin (30 mg/kg, i.p) was given at the 28th day, valsartan (30 mg.kg(-1).d(-1), n = 13) or placebo (n = 11) was administered at the 35th day to rats with fasting blood glucose > or = 11.1 mmol/L per gavage for another 12 weeks. Control rats (n = 8) were fed with regular chow. Fasting blood glucose was monitored throughout the study, left ventricular function was determined by echocardiography, myocardial collagen content quantified after Masson-staining and myocardial mRNA expression of TRB(3) detected by quantification real-time RT-PCR at the end of study. RESULTS: Cardiac function was significantly improved (EF: 74% +/- 10% vs. 66% +/- 7%, P < 0.05), myocardial collagen content decreased (13.23 +/- 3.14 vs. 16.92 +/- 3.18, P < 0.05) in rats with DCM treated with valsartan. Moreover, TRB(3) mRNA was significantly increased in rats with DCM compared to control rats (0.0198 +/- 0.0082 vs. 0.1108 +/- 0.0933, P < 0.05) and the increase could be significantly attenuated by valsatran (0.0367 +/- 0.0234, P < 0.05 vs. DCM). A significant positive correlation was observed between myocardial TRB(3) mRNA and myocardial collagen content (r = 0.67, P < 0.05) and between TRB(3) mRNA and fasting blood glucose (r = 0.69, P < 0.05) in rats with DCM. CONCLUSION: Our results show for the first time that myocardial TRB(3) mRNA is upregulated in rats with DCM and which could be down-regulated by valsartan.