Regulating effects of transforming growth factor-β1 on gene expressions of MMP-1 and TIMP-1 mRNA in human hyaline chondrocytes

Objective To investigate the role of transforming growth factor -β1(TGF-β1) in regulating gene expression of the matrix metalloproteinase-1 (MMP-1) and its inhibitor, the tissue inhibitor of metalloproteinase -1(TIMP-1) in human hyaline chondrocytes so as to have a better understanding of the mechanism of cartilage injury in osteoarthritis. Methods In the experiment, human hyaline chondrocytes were harvested enzymatically and cultured in DMEM and given respectively TGF-β1 of 1 ng/mL, 10 ng/mL and 100 ng/mL, 1 ng/mL TGF-β1+10 ng/mL IL-1β, 10 ng/mL TGF-β1+10 ng/mL IL-1β, 100 ng/mL TGF-β1+10 ng/mL IL-1βbefore they were cultured for another 12 hours. The MMP-1 and TIMP-1 mRNA levels of passaged monolayer cell cultures of human hyaline chondrocyte were assessed by reverse transcriptase polymerase chain reaction (RT-PCR) and fluorescent quantitative PCR (FQ-PCR). Results Normal human chondrocytes expressed MMP-1 and TIMP-1 mRNA. In the groups treated with TGF-β1 and IL-1β, TGF-β1 could decrease the MMP-1 mRNA level, but increase TIMP-1 mRNA expression level. The difference was significant (P 0.05) and the levels of MMP-1 and TIMP-1 mRNA expression had significant association with the dosages of TGF-β1. Conclusion Our results show that TGF-β1 may have a crucial effect on chondrocytes by regulating the balance between the expressions of MMP-1 mRNA and TIMP-1 mRNA, which are known to be important in osteoarthritis development, and have an antagonistic effect on IL-1βin osteoarthritis.