Effect of mesenchymal stem cells on doxorubicin-induced fibrosis

ABSTRACT

The aim of this study was to test the effect of intravenous injection of mesenchymal stem cells [MSCs] on doxorubicin [DOX]-induced fibrosis in the heart. We investigated the mechanisms that possibly mediate this effect. In this experimental study, fibrosis in the myocardium of adult male Wistar rats [weights 180-200 g, 9-10 weeks of age, total n=30] was created by DOX administration. DOX [2.5 mg/kg] was administered intraperitoneally 3 times a week, for a total dose of 15 mg/kg over a period of 2 weeks. MSCs from Wistar rats were separated and cultured in Dulbecco's modified eagle medium [DMEM]. The condition medium [CM] which contained factors secreted by MSCs was also collected from MSCs cultured in serum-free DMEM. Two weeks after the first injection of DOX, MSCs, CM and standard medium [SM] were transplanted via intravenous injection. Four weeks after transplantation, histological [Masson's trichrome staining for fibrosis detection] and molecular [real-time polymerase chain reaction [RT-PCR]] analyses were conducted. In addition, insulin-like growth factor [IGF-1] and hepatocyte growth factor [HGF] in the CM were measured with an enzyme-linked immunosorbent assay [ELISA]. For immunosuppressive treatment, cyclosporine A was given [intraperitoneally, 5 mg/kg/day] starting on the day of surgery until the end of study in all groups. Fibrosis rate and relative gene expression were compared by analysis of variance [ANOVA] and post-Tukey's test. HGF and [IGF-1 in the CM were analyzed by independent sample t test. P<0.01 was considered statistically significant. Our data demonstrated that intravenously transplanted MSCs and CM significantly reduced fibrosis and significantly increased Bcl-2 expression levels in the myocardium compared to the DOX group [p<0.01]. However, there was no significant difference between Bax expression levels in these groups. In addition, secretion of HGF and IGF-1 was detected in the CM [p<0.01]. We conclude that intravenous transplantation of MSCs and CM can attenuate myocardial fibrosis and increase Bcl-2 expression. This may be mediated by paracrine signaling from MSCs via anti-fibrotic and anti-apoptotic factors such as HGF and IGF-1