Sika pilose antler type I collagen promotes BMSC differentiation via the ERK1/2 and p38-MAPK signal pathways

Context: Sika pilose antler type I collagen (SPC-I) have been reported to promote bone marrow mesenchymal stem cell (BMSC) proliferation and differentiation. However, the underlying mechanism is still unclear.Objective: This study investigates the molecular mechanisms of SPC-I on the BMSC proliferation and differentiation of osteoblast (OB) in vitro.Material and methods: The primary rat BMSC was cultured and exposed to SPC-I at different concentrations (2.5, 5.0 and 10.0mg/mL) for 20days. The effect of SPC-I on the differentiation of BMSCs was evaluated through detecting the activity of alkaline phosphatase (ALP), ALP staining, collagen I (Col-I) content, and calcified nodules. The markers of osteoblastic differentiation were evaluated using RT-PCR and Western-blot analysis.Results: SPC-I treatment (2.5mg/mL) significantly increased the proliferation of BMSCs (p<0.01), whereas, SPC-I (5.0 and 10.0mg/mL) significantly inhibited the proliferation of BMSCs (p<0.01). SPC-I (2.5mg/mL) significantly increased ALP activity and Col-I content (p<0.01), and increased positive cells in ALP staining and the formation of calcified nodules. Additionally, the gene expression of ALP, Col-I, Osteocalcin (OC), Runx2, Osterix (Osx), ERK1/2, BMP2 and p38-MAPK, along with the protein expression of ERK1/2, p-ERK1/2, p-p38 MAPK were markedly increased in the SPC-I (5.0mg/mL) treatment group (p<0.01) compared to the control group.Discussion and conclusions: SPC-I can induce BMSC differentiation into OBs and enhance the function of osteogenesis through ERK1/2 and p38-MAPK signal transduction pathways and regulating the gene expression of osteogenesis-specific transcription factors.