Anti-fibrotic effect of adipose-derived mesenchymal stem cell conditioned medium in muscle fibrosis

Recent investigations have demonstrated that the administration of MSC in mouse model of diseases provided beneficial effects. On the other hand, human adipose-derived MSC condition medium (ADSC-CM) is reported as containing beneficial secreted factors, but its role in muscle fibrosis has not been identified. The aim of this study was to investigate the inhibitory effects of MSC-CM in muscle fibrosis in vitro using the C2C12 murine muscle, myoblast cell line.

C2C12 cells were cultured overnight in 0.1% albumin-Dulbecco's Modifies Eagle's Medium (DMEM). The cells were then pre-incubated in ADSC-CM for 20 min, treated with 2.5-10 ng/mL human TGFβ1 for 8-72 hours and analyzed using RT-qPCR, Western blot and immunofluorescent staining.

Treatment with 20% ADSC-CM for 3 days suppressed αSMA protein expression in TGFβ1 treated C2C12 cells. ADSC-CM stimulated the proliferation of C2C12 cells in a dose-dependent manner. Furthermore, TGFβ1 induced Acta2/αSMA mRNA expression which was inhibited by ADSC-CM treatment for 8 hours. Decorin, one of the dermatan sulfate proteoglycans and an endogenous inhibitor of TGFβ1, was expressed in ADSC-CM, but not in TGFβ1 pre-incubated ADSC-CM.

Our studies provide useful information for establishing anti-fibrotic mechanism(s) of ADSC-CM, thus facilitating potential application to prevent muscle fibrosis.