目的:研究肥厚心脏心室重塑及逆重塑过程中Akt/GSK3、MAPKs和NF-κB信号通路的变化。方法:以Lewis大鼠行腹主动脉缩窄术,建立压力超负荷性心肌肥厚模型。将肥厚心脏移植到同源Lewis大鼠腹部,建立压力卸负荷模型。对各组心肌取材进行病理学评价。Western blotting法检测心肌组织中相关信号通路蛋白的表达。结果:在心肌肥厚大鼠心脏中Akt/GSK3β、MAPKs和NF-κB磷酸化水平均显著升高,移植卸负荷后除p38MAPK和JNK外,其它蛋白磷酸化水平均显著降低。结论:肥厚心脏经异位移植卸负荷后产生逆重塑现象,Akt/GSK3、ERK1/2和NF-κB信号通路的改变参与其中,该结果为临床心室逆重塑的研究提供了实验依据。
AIM: Heterotopic transplantation of rat hypertrophic hearts has been shown to reverse chamber enlargement and regress cardiac myocyte hypertrophy. The purpose of this study was to gain a better understanding of molecular changes associated with the beneficial reverse remodeling after pressure unloading of hypertrophic heart. METHODS: Stable cardiac hypertrophy was induced by abdondnal aortic constriction (AAC) in Lewis rats (6 weeks). Left ventricular (LV) pressure unloading was induced by heterotopic transplantation of hypertrophic hearts ( AAC - HT) and/or normal hearts (NL- HT) (2 weeks). We measured heart weight (HW) and LV weight (LVW) of all groups. Cross -sectional area of cardiomyocyte was assessed by hematoxylin/eosin staining. We further analyzed the regulation of prohypertrophic signaling pathways of mitogen -activated protein kinases (MAPKs), Akt/GSK3βand NF-κB in both transplanted groups by Western blotting. RESULTS : The HW and LVW in AAC hearts were higher ( P 〈 0. 05 ) than those in normal controls, but the transplanted hearts in AAC - HT group showed a significant reduction in HW and LVW compared to the AAC hearts. Pressure unloading induced a decrease in cardiomyocyte size in AAC - HT and NL - HT hearts. A significant decrease in phosphorylation of p44/p42 MAP kinases (ERK), Akt, GSK3β and NF - KB was detected in AAC -HT hearts, but the phosphorylation of p38 MAP kinase and Jun -N -terminal kinase (JNK) were not changed compared to AAC hearts. The phosphorylation of MAPKs, Akt/GSK3β and NF-κB showed no difference between NL - HT hearts and normal controls. CONCLUSION : Pressure unloading of the hypertrophic heart caused a reverse remodeling through regulating the ERK, Akt/GSK3β and NF-κB signal pathways which act as potential target pathways for reversal of LV hypertrophy.