[Experimental study on chondrogenic differentiation of rabbit adipose-derived stem cells treated with growth differentiation factor 5].

OBJECTIVE: To investigate the feasibility and effect of inducing adipose-derived stem cells (ADSCs) treated with growth differentiation factor 5 (GDF-5) to undergo chondrogenic differentiation in vitro.

METHODS: Six healthy Japanese rabbits aged 3 months (2-3 kg) of clean grade were chosen, irrespective of sex. ADSCs were isolated and cultured with collagenase digestion, then were detected and identified by vimentin immunohistochemistry and CD44, CD49d, CD106 immunofluorescence staining. ADSCs at passage 3 were used and the cell density was adjusted to 1 x 10(6)/mL, then the ADSCs were treated with 0, 10, 100 ng/mL GDF-5 and common cultural medium, respectively. The morphology changes of the induced ADSCs were observed by inverted contrast phase microscope and their growth state were detected by MTT. The mRNA quantities of Col II and proteoglycan expressed by the induced ADSCs were detected with RT-PCR. The Col II proteoglycan synthesized by the induced ADSCs were detected with alcian blue staining, toluidine blue staining, immunohistochemistry staining, and Western blot method.

RESULTS: ADSCs mostly presented small sphere, fusiform and polygon shape with positive expression of CD44 and CD49d and negative expression of CD106 and vimentin. The ADSCs treated with 100 ng/mL GDF-5 presented sphere or sphere-like change and vigorous proliferation. The mRNA quantities of Col II and proteoglycan synthesized by the induced ADSCs treated with 0, 10, 100 ng/mL GDF-5 and common cultural medium increased in a dose-dependent manner at 7 days. There were significant differences among all the groups (P < 0.05), except that no significant difference was evident between the 0 ng/mL group and the 10 ng/mL group (P > 0.05). When ADSCs were treated with 100 ng/mL GDF-5 for 14 days, the Col II and the mRNA and protein quantities of proteoglycan reached the peak, and the results of alcian blue, toluidine blue and Col II immunohistochemistry staining were positive.

CONCLUSION: ADSCs treated with certain concentration of GDF-5 have higher expression of Col II and proteoglycan and possess partial biological function of chondrocyte.