Objectives: It has been proposed that adipogenic potential of mesenchymal stem cells (MSCs) depends on transcription factors, age, hormones, growth factors, and donor. Adipogenesis is negatively regulated by multiple signaling pathway such as transforming growth factor β (TGF-β) and Wnt/β-catenin signaling pathway. Adipogenic differentiation potential of equine adipose-derived MSCs (e-ADSCs) strongly depends on the components of the differentiation media, but he related mechanisms still are unclear. This study aimed to investigate the role of TGF-β1 and CTNNB, as two key members of TGF-β and Wnt/β-catenin signaling pathways on adipogenic differentiation of e-ADSCs. Materials and Methods: e-ADSCs were isolated from the fat tissue of gluteal region and expanded in vitro. The cells at passages 5 were seeded and maintained in usual adipogenic culture medium. 75 % confluency of cells was considered as day 0 and cells were harvested at days 1, 3, 5 and 7. Then, total RNA was extracted and transcribed into cDNA using commercially available kits. Quantitative RT-PCR (qPCR) was performed using a SYBR green master mix and specific primers for GAPDH (as internal control), TGF-β1 and CTNNB. Cells at day 0 were used as calibrator, data were normalized by GAPDH and analyzed using one way ANOVA. Adipogenic differentiation was assessed by Oil Red O specific staining. Results: At the mRNA level, the expression of TGF-β1 was significantly up regulated at days 3, 5 compared with day 1. Although mRNA level of TGF-β1 was significantly reduced at day7, but no significant difference was observed comparison to day 1. The expression of CTNNB were upregulated at all- time points compared with day1. Conclusions: The upregulated expression of both TGF-β1 and CTNNB supports the view that TGF-β and Wnt signaling pathways may are one of the probable mechanisms involved in adipogenic inhibition of e-ADSCs.

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