梗死心肌组织裂解液对鼠骨髓间充质干细胞诱导分化作用的体外研究

 目的 探讨梗死心肌组织裂解液对骨髓间充质干细胞（MSC）向心肌细胞分化的诱导作用。 方法 取 SD 大鼠梗死区心肌组织及其周围区域正常心肌组织分别制备梗死心肌组织裂解液和正常心肌组织裂解液；用 Balb/c 小鼠骨髓细胞进行 MSC 培养，取生长较好的第 2 代 MSC 制备 MSC 贴片，分别用 DMEM 培养基（空白对照组）、加入正常心肌组织裂解液的 DMEM 培养基（正常心肌组织裂解液组）和加入梗死心肌组织裂解液的 DMEM 培养基（梗死心肌组织裂解液组）培养。取各组培养 14 d 的 MSC，透射电镜下观察细胞超微结构；并进行免疫细胞化学染色，观察 α-肌动蛋白（actin）、心肌特异性转录因子 4（GATA-4）、心肌特异性肌球蛋白重链（MHC）、心肌特异性肌钙蛋白 T（cTnT）、心肌特异性肌钙蛋白 I（cTnI）、心肌增强因子 2（MEF-2）、连接蛋白（Cx）43 和 Cx45 的表达情况。 结果 超微结构观察显示空白对照组细胞器结构正常；正常心肌组织裂解液组细胞内未见明显的肌丝样结构；而梗死心肌组织裂解液组部分细胞内可见细小的肌丝样结构。免疫细胞化学染色分析显示，空白对照组 MSC 不表达心肌细胞特异性蛋白；正常心肌组织裂解液组 MSC 仅表达 α-actin；而梗死心肌组织裂解液组 MSC 表达 α-actin、GATA-4、MHC、cTnT、cTnI 和 MEF-2 等心肌特异性标志蛋白，但不表达 Cx43 和 Cx45。 结论 梗死心肌组织裂解液可以诱导骨髓间充质干细胞向心肌样细胞分化。

Differentiation of mouse bone marrow mesenchymal stem cells induced by infarcted myocardium lysate in vitro

Objective To investigate the effect of infarcted myocardium lysate on the differentiation of mouse bone marrow mesenchymal stem cells (MSCs) in vitro. Methods Infarcted myocardium lysate and normal myocardium lysate were respectively obtained from the infarcted and adjacent normal myocardia in the ventricles of six-week-old Sprague-Dawley rats. The Second-passage MSCs isolated from Balb/c mouse were purified and then incubated in 3 different media (group A: DEDM (control); group B: DEDM containing normal myocardium lysate; and group C: DEDM containing infarcted myocardium lysate). On day 14, the MSCs were harvested from the media, and observed under a transmission electron microscope. Then, the expressions of α-actin, GATA-4, MHC, cTnT, cTnI, MEF-2, Cx43 and Cx45 in the MSCs were detected by immunohistochemistry. Results Transmission electron microscopy showed normal organelle in the control group; myofilament structure was not obviously shown in the group B, but was observed in the group C. Immunohistochemistry found that no cardiac-specific protein was expressed in the MSCs of the control group, while in the group B α-actin expression was detected. In the group C, the MSCs expressed α-actin, GATA-4, MHC, cTnT, cTnI, and MEF-2, but not Cx43 and Cx45. Conclusion Infarcted myocardium lysate can induce MSCs differentiation into myocardial-like cells.