中文摘要：

本研究旨在探讨心肌肌浆网Ca^2＋-ATP酶2a（sarcoplasmic reticulum Ca2＋-ATPase2a,SERCA2a）基因过表达对正常犬离体心肌细胞收缩功能的影响。通过胶原酶消化法分离犬心肌细胞,将分离的心肌细胞分为未转染组、空载体组、SERCA2a转染组,转染载体为含绿色荧光蛋白基因的重组腺病毒载体,转染后均培养48h。利用免疫印迹法检测各组心肌细胞SERCA2a蛋白表达水平,并通过单细胞收缩动态边缘检测系统测定各组心肌细胞收缩功能的改变。结果显示,与未转染组相比,SERCA2a转染组SERCA2a蛋白表达水平明显升高,基础状态心肌收缩百分比和药物刺激条件下心肌最大收缩百分比均明显升高,达到峰值收缩时间（TTP）和50%舒张时间（R50）亦明显延长,差异具有显著性;而空载体组各项指标均无显著变化。以上结果提示,SERCA2a基因转导过表达能够增强正常犬心肌细胞的收缩功能。

英文摘要：

The present study is aimed to study the effect of sarcoplasmic reticulum Ca2＋-ATPase 2a（SERCA2a） gene transfer on the contractile function of isolated cardiomyocytes of canines.The cardiomyocytes were isolated with collagenases.The isolated cardiac cells were divided into untransfected group,empty vector group and SERCA2a-transfected group.Recombinant adenovirus vector carrying enhanced green fluorescent protein gene was used for SERCA2a gene delivery.The expression of SERCA2a protein in cardiomyocytes was determined by Western blot.Contractile function of cardiomyocytes was measured with motion edge-detection system of single cell at 48 h after transfection.The results showed,compared with untransfected group,SERCA2a protein level,percentage of peak contraction amplitude under normal condition,percentages of peak contraction amplitude under Ca2＋ or isoproterenol stimulation,time-to-peak contraction（TTP） and time-to-50% relaxation（R50） in SERCA2a-transfected group all increased significantly.While all the above indices in empty vector group did not show any differences with those in untransfected group.These results suggest that the overexpression of SERCA2a by gene transfer may enhance the contraction function of canine myocardial cells.