Fig. 4. Effects of treatment of CoCl₂ on the chondrogenic differentiation.

(A) C3H/10T1/2 cells were pre-incubated with 0.1 mM CoCl₂ for 0 h, 24 h, or 48 h. After incubation, the cells shifted to a chondrogenic medium and cultured for 14 days. The cells were then stained with Alcian blue. (B) C3H/10T1/2 cells were pre-incubated with 0.1 mM CoCl₂ for 0 h, 24 h, or 48 h. After incubation, the cells were shifted to a chondrogenic medium and cultured for 3 days. Total cellular RNA was extracted and gene expression of the chondrogenic markers aggrecan, sox9, and Col 2A1 was assessed by semi- quantitative RT-PCR. Expression of actin was examined in the same sample as a control for the amount of present reverse-transcribed cDNA. (C) Effects of treatment of CoCl₂ during chondrocyte differentiation. C3H/ 10T1/2 cells were pre-incubated with 0.1 mM CoCl₂ for 0 h, 24 h, or 48 h. After incubation, the cells were replaced with chondrogenic medium and cultured for 10 days. At indicated times, total cellular RNA was extracted and gene expression of the chondrogenic makers aggrecan, sox9, and Col 2A1 was assessed by qRT-PCR. Values shown are normalized to β-actin levels.