论文部分内容阅读
目的观察压力超负荷所致肥大心肌中增殖细胞核抗原和周期素D1的表达变化,探讨其与心肌肥大的相互关系。方法采用腹主动脉缩窄法建立大鼠心肌肥大模型,在术后不同时间点用颈总动脉插管法动态测定心功能并观察左心室体重比及心肌细胞横径的变化,用免疫组织化学方法检测心肌细胞增殖细胞核抗原和周期素D1表达变化,分别计算其阳性细胞占总心肌细胞数的比率。结果腹主动脉缩窄术后各时间点左心室体重比及心肌细胞横径进行性增高(P<0.05),同时心功能也进行性增强(P<0.05)。增殖细胞核抗原和周期素D1阳性率术后1周时显著增高(P<0.01),随后逐步回降,6周时同对照组相比差异无显著性。结论心肌肥大中不仅有心肌细胞体积的增大而且早期伴有增殖指标高表达,这种增殖指标的高表达随着心脏对负荷的适应逐步回降至正常水平,而心肌细胞体积仍进行性增大。
Objective To observe the expression of proliferating cell nuclear antigen (PCNA) and cyclin D1 in hypertrophic myocardium induced by pressure overload and to explore the relationship between them and cardiac hypertrophy. Methods The rat model of cardiac hypertrophy was established by abdominal aorta constriction. Heart function was measured by carotid artery intubation at different time points and the changes of left ventricular mass ratio and cardiac myocyte diameter were observed. Immunohistochemistry Methods The expression of proliferating cell nuclear antigen (PCNA) and cyclin D1 in cardiomyocytes were measured and the ratio of positive cells to total cardiomyocytes was calculated. Results The weight ratio of left ventricle and the diameter of cardiomyocytes increased progressively (P <0.05) at the same time point after abdominal aortic constriction, meanwhile the cardiac function was also enhanced (P <0.05). The positive rates of proliferating cell nuclear antigen and cyclin D1 were significantly increased at 1 week after operation (P <0.01), and then gradually decreased. There was no significant difference at 6 weeks from the control group. Conclusions Cardiomyocyte hypertrophy not only increases the volume of cardiomyocytes but also increases the expression of proliferation index in early stage. The high expression of this proliferation index gradually regresses to the normal level as the heart adapts to the load, while the volume of cardiomyocytes is progressively increased Big.