平滑肌细胞移植提高大鼠心肌缺血模型心功能的可行性实验研究

Feasibility in improving heart function by smooth muscle cells transplantation into ischemic myocardium

目的 初步探讨移植平滑肌细胞对大鼠冠脉结扎心肌缺血模型心功能的提高作用。方法 用酶消化法从 胎鼠胃中分离、提取平滑肌细胞,进行体外培养、扩增。结扎大鼠左冠状动脉前降支,制作心肌缺血模型。细胞移植组 (n=10)将体外培养、BrdU标记的平滑肌细胞,注射移植到冠脉结扎后2周形成的心肌梗死区中;对照组(n=10)用同样的 方法注射等量不含血清的DMEM培养液;两组动物术后均每日皮下注射环胞霉素A抑制免疫排斥反应。超声检查评估移 植前、后大鼠的心功能状况。取大鼠心脏标本做抗BrdU、抗α SMA免疫组化染色,检测心肌梗死区中植入的平滑肌细胞的 存活情况。结果 移植后4周,平滑肌细胞存活于心肌梗死区,并形成肌样组织。与对照组比较,移植组左室前游离壁厚 度明显增加[(2.51±0.22)mmvs(1.32±0.16)mm,P<0.01],左室舒张末容积(LVEDV)明显减小[(1.23±0.12)mlvs(1.92 ±0.18)ml,P<0.01],左室射血分数(LVEF)显著提高[(56.7±6.8)%vs(32.3±2.9)%,P<0.01]。结论 平滑肌细胞移 植后能存活于心肌梗死区,并改善缺血心肌的心功能。

Objective To investigate the feasibility in improving the heart function by smooth muscle cells transplantation into the ischemic myocardium model established by coronary artery ligation. Methods Myocardial infarct was produced by ligation of the left coronary artery. At 2 weeks after establishment of myocardial infarct, cultured fetal rat gatric smooth muscle cells marked with BrdU were transplanted into the ischemic myocardium by direct injection (transplantation group, n=10), or culture medium alone (control group, n=10). Heart function was assessed by echocardiography before and at 4 weeks after transplantation. At 4 weeks after transplantation, the hearts were harvested. The transplanted smooth muscle cells were assessed by immunostaining against BrdU and α-SMA. Results The injected fetal smooth muscle cells survived in the infarcted regions and formed muscle-like tissues at the site of transplantation at 4 weeks after transplantation. The grafts thickened the wall of the left ventricle [(2.51±0.22) mm vs (1.32±0.16) mm, P<0.01] and were associated with reduced LV end-diastolic volumes [(1.23±0.12) ml vs (1.92±0.18) ml, P<0.01], enhanced LV ejection fraction [(56.7±6.8)% vs (32.3±2.9)%, P<0.01], prevented cardiac dilatation, and improved the ventricular function. Conclusion Smooth muscle cells transplantation into the ischemic myocardium can improve the injured heart function.