EFFECTS OF SEVERAL CYTOKINES ON THE FUNCTIONS OF FETAL RAT OSTEOBLAST-LIKE CELLS IN VITRO

EFFECTS OF SEVERAL CYTOKINES ON THE FUNCTIONS OF FETAL RAT OSTEOBLAST-LIKE CELLS IN VITRO

Effects of several cytokines(IL -1β, TNFα, and IFNγ) 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-1β, TNFα, and IFNγ, respectively or combined. And acid phosphatase was determined by biochemical method. Alkaline phosphatase was assayed to determine the effects of IL-1β, TNFα, and IFNγ 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-1β and TNFα, whereas decreased by IFNγ, However, no significant changes in alkaline phosphatase activity was observed when the osteoblast-like cells were treated with IL-1β and TNFα. Interestingly, IFNα showed stimulatory effect on alkaline phosphatase activity. The number of calcified nodules was decreased by treatment of cultures with 1ng/ml IL -lβ, 20ng/ml TNFα, and 500 u/ml IFNγ 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.