目的： Ghrelin是近年发现的一种新的生长激素释放肽，具有心血管保护效应。本研究旨在观察心肌梗死(MI)后Ghrelin及其受体GHSR-1a的动态表达及其变化。方法30只SD雄性大鼠，随机分为四组，分别为假手术组(6只)，心肌梗死后3 d组(8只)，梗死7 d组(8只)，梗死28 d组(8只)。采用冠状动脉结扎法制作心肌梗死模型，假手术组只在冠状动脉下穿线，但不结扎。采用实时定量PCR方法检测梗死边缘心肌Ghrelin及GHSR-1a mRNA表达，免疫印迹法检测梗死边缘心肌Ghrelin及GHSR-1a蛋白表达及分布。结果与假手术组比较，MI后3 d、7 d、28 d梗死周边区域心肌中Ghrelin mRNA表达明显降低(P<0.05)，且呈逐渐下降趋势；而GHSR-1a mRNA表达显著增加(P<0.05)；梗死3 d组与梗死7 d组差异无统计学意义(P>0.05)。免疫印迹显示假手术组大鼠心肌显示出了较强的Ghrelin阳性表达，而心肌梗死后Ghrelin阳性表达明显降低(P<0.05)；与此相反， GHSR-1a蛋白表达在梗死后明显增加(P<0.05)。结论 Ghrelin/GHSR-1a系统在梗死后心脏重构中可能起着重要作用，并可作为防止心脏重构的一个新的干预靶点。%Objective Ghrelin is a novel growth hormone-releasing peptide, which has been shown to exert ben-eficial effects on cardiac function and ventricular remodeling. The present study aimed to investigate the expression of ghrelin and the growth hormone (GH) secretagogue receptor 1a (GHSR-1a). Methods After ligation of the anterior de-scending artery (LAD), adult male Sprague-Dawley rats were randomized to 3 d, 7 d and 28 d groups, with eight rats in each group. Another six rats underwent thoracotomy and pericardiotomy, but not LAD ligation (Sham group). Expressions of both ghrelin and GHSR-1a were assessed by means of immunohistochemistry and real-time PCR. Results Cardiac expression of ghrelin increased on day 3, 7 and 28 compared with the sham group (P<0.05). In contrast, the GHSR-1a mRNA levels increased during the same days (P<0.05). Decreased expression of ghrelin and increased expression of GH-SR-1a were also observed in infarcted heart. Conclusion The ghrelin/GHSR-1a system may play an important role in regulating cardiac remodeling after MI and provide a potential pharmacological target for treating cardiac remodeling.
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