Effects of several cytokines on the functions of fetal rat osteoblast-like cells in vitro

Han, Hee Sung; Kim, Jung Keun; Chang, Young Il

Abstract

Effects of several cytokines(IL -1beta, TNFalpha, and IFNgamma) have been examined on fetal rat osteoblast-like cells. To investigate whether cytokines play direct causal roles in production of lysosomal enzyme, fetal rat osteoblast-like cells were treated with IL-1beta, TNFalpha, and IFNgamma, respectively or combined. And acid phosphatase was determined by biochemical method. Alkaline phosphatase was assayed to determine the effects of IL-1beta, TNFalpha, and IFNgamma on the expression of this enzyme. And also experiment of calcified nodule formation was performed to assess the effects of cytokines on the bone-forming activity of osteoblast-like cells in vitro. Acid phosphatase activity was significantly increased by the addition of IL-1beta and TNFalpha, whereas decreased by IFNgamma, However, no significant changes in alkaline phosphatase activity was observed when the osteoblast-like cells were treated with IL-1beta and TNFalpha. Interestingly, IFNalpha showed stimulatory effect on alkaline phosphatase activity. The number of calcified nodules was decreased by treatment of cultures with 1ng/ml IL -lbeta, 20ng/ml TNFalpha, and 500 u/ml IFNgamma continuously for 21 days, while considerable number of calcified nodules were formed in control group of osteoblast-like cell in culture for 21 days. These results seem to suggest that cytokines may play crucial roles in bone remodeling through the direct action on the osteoblast-like cell.