Abstract: Objective: To observe the effects of velvet antler collagen type Ⅰ (VACT Ⅰ) on the proliferation and cell cycle of bone marrow mesenchymal stem cells (BMSCs), and to explore its relationships with the expressions of type Ⅱ collagen and aggrecan. Methods: The healthy male SD rats aged 4 weeks were chosen and the BMSCs were extracted by differential adhesion method and cultivated. The experiment was divided into blank control group, transforming growth factor β3(TGF-β3) (10 μg·L^-1) group, and different concentrations (1.25, 2.50, 5.00, 10.00, and 20.00 g·L^-1) of VACT I groups. CCK-8 assay was used to detect the proliferation rates of BMSCs in various groups. The levels of bone morphogenetic protein-4 (BMP-4) and transcription factor Sox9 in the cell supernatant in various groups were detected by ELISA method. The percentages of BMSCs in different cell cycles in various groups were detected by flow cytometry. The expression levels of type Ⅱ collagen and aggrecan mRNA and proteins in BMSCs in various groups were detected by RT-PCR and Western blotting methods, respectively. Results: Compared with blank control group, the proliferation rates of BMSCs of the rats in 2.50-20.00 g·L^-1 VACT Ⅰ groups were significantly decreased (P<0.05 or P<0.01). The ELISA results showed that compared with blank control group, the levels of BMP-4 and Sox9 in the cell supernatant of the rats in TGF-β3 group and different concentrations of VACTⅠ groups were significantly increased (P<0.05 or P<0.01). The flow cytometry results showed that compared with blank control group, the percentages of BMSCs in different cell cycles of the rats in TGF-β3 group and different concentration of VACT Ⅰ groups had no significant differences(P>0.05). The RT-PCR results showed that compared with blank control group, the mRNA expression levels of type Ⅱ collagen and aggrecan in TGF-β3 group and different concentrations of VACT Ⅰ groups were significantly increased (P<0.05). The Western blotting results showed that compared with blank control group, the expression levels of type Ⅱ collagen and aggrecan proteins in TGF-β3 group and different concentrations of VACTⅠ groups were significantly increased (P<0.05 or P<0.01). Conclusion: VACTⅠcan promote the release of BMP-4 and Sox9 from cells, increase the expression levels of type Ⅱ collagen and aggrecan, and inhibit the proliferation of BMSCs. It is a potential chondrogenic differentiation inducer.

Key words: velvet antler collagen type Ⅰ, bone marrow mesenchymal stem cells, chondrogenesis, type Ⅱ collagen, aggrecan