目的　观察骨髓间充质干细胞(MSCs)在治疗损伤心肌细胞中的分子机制，明确Wnt/β-catenin信号通路是否在其发挥着作用。方法　分离、鉴定并培养心肌细胞72 h后分为3组，A组为正常心肌细胞组、B组为阿霉素损伤组(1 mg/L阿霉素作用心肌细胞4 h建立)、C组为MSCs与损伤心肌细胞共培养组，继续培养72 h后，流式细胞仪检测心肌细胞凋亡，应用Western blot法检测β-catenin、c-Myc、p53蛋白的表达。结果　阿霉素损伤组的心肌细胞凋亡率为(26.58±3.89)%，对照组为(0.74±0.65)%，MSCs与损伤心肌细胞共培养组为(7.72±0.90)%，差异有统计学意义(F=98.13，P<0.001)。经两两比较发现，阿霉素损伤组的凋亡率高于对照组；而共培养组凋亡率低于阿霉素损伤组，差异均有统计学意义(P<0.05)。阿霉素损伤组的β-catenin、c-Ｍyc及p53蛋白表达水平均高于MSCs与损伤心肌细胞共培养组，两组间差异均有统计学意义(P均<0.01)；对照组上述3种蛋白表达不能测出。结论　MSCs可抑制阿霉素诱导的心肌细胞凋亡，其分子机制可能与Wnt/β-catenin通路的抑制有关。

Objective　To investigate the molecular mechanism of bone marrow mesenchymal stem cells (MSCs) in the treatment of injured cardiomyocytes and to explore the role of Wnt/β-catenin signaling pathway in this process. Methods After isolation, identification and culture for 72 hours, cardiomyocytes were divided into 3 groups: normal cardiomyocytes group (Group A), injured cardiomyocytes group (induced by 1 mg/L doxorubicin for 4 hours, Group B) and co-culture group (doxorubicininjured cardiomyocytes co-cultured with MSCs, Group C). After 72 hours of culture, apoptosis of cardiomyocytes was detected by flow cytometer, and the expression of β-catenin, c-Myc and p53 protein were tested by western blot. Results The apoptosis rates of cardiomyocytes in Group A, B and C were 0.74±0.65, 26.58±3.89 and 7.72±0.90, respectively, and the difference was significant (F=98.13, P<0.001). Through pairwise comparison, it was found that the apoptosis rate of cardiomyocytes in Group B was significantly higher than that in Group A and C (P<0.05). The results of western blot showed that the protein expression levels of β-catenin, c-Myc and p53 in Group B were significantly higher than those in Group C (P<0.01). However, in Group A, the protein expression of β-catenin, c-Myc and p53 could not be measured by western blot. Conclusions MSCs have significant anti-apoptotic effect on doxorubicin-induced cardiomyocyte injury and the molecular mechanism may related to the inhibition of Wnt/β-catenin signaling pathway.