Effects of FGF2 administration for different time periods on chondrocytes

Abstract

Objective To study the effects of fibroblast growth factor 2 (FGF2) on the proliferation and gene expression profiles of rabbit articular chondrocytes in vitro after different time periods of stimulation. Methods The chondrocytes were isolated and cultured in vitro, and the 3rd generation cells were harvested. Cells were divided into three groups. In the group 1 (FGF2 short-time action group), chondrocytes were cultured in medium with FGF2 for one day, and then transferred to fresh culture medium without FGF2 and cultured for another 6 days. In the group 2 (FGF2 long-time action group), chondrocytes were cultured in medium with FGF2 for 7 days. In the Group 3 (control group), chondrocytes were cultured in culture medium without FGF2 for 7 days. After culture for 1, 3, and 7 days, the proliferation of chondrocytes in the all groups was detected respectively. Following extraction of mRNA, the gene expressions of BMP2, BMP4, SOX9 and COL2A1 of the chondrocytes in the all groups were determined by quantitative real-time polymerase chain reaction (qRT-PCR). The content of type II collagen was measured via immunofluorescence staining. Results Compared with the control group, FGF2 promoted the proliferation of chondrocytes in the short-and long-time action groups and there was no significant difference between the two FGF2-treated groups. The results of qRT-PCR indicated that different treatment induced different gene expression profile. Particularly, compared with the control group and the FGF2 long-time action group, the expression of BMP2, BMP4, SOX9 and COL2A1 in the short-time action group were significantly upregulated at the 7th day. Immunofluorescence intensity of type II collagen in the group 1 was stronger than that in the control group and group 2. Conclusions Different administration of FGF2 for different time periods induced different responses of chondrocytes. Short-term FGF2 stimulation was more beneficial to maintain the phenotype of chondrocytes and the synthesis of extracellular matrix. Key words: Fibroblast growth factor 2; Chondrocytes; Long-time action; Short-time action