Recombinant interferon-gamma is a potent inhibitor of osteoblastic cell functions

Interleukin-1 and tumor necrosis factor-stimulated bone resorption is mediated by osteoclast-activating factor elaborated by osteoblasts. Recombinant interferon-gamma inhibits stimulation of bone resorption by these cytokines. We examined here the effects of recombinant mouse interferon-gamma (rmIFN-G) on DNA and collagen synthesis, and on alkaline phosphatase (ALP) activity, in the osteoblastic cell line (MC3T3-E1) under confluent culture conditions. Addition of rmIFN-G to the cells markedly inhibited their DNA synthesis and ALP activity in dose- and culture time-related manner. Also we found that rmIFN-G decreased markedly collagen synthesis at day 3 after addition of the agent. These data indicate that rmIFN-G is a potent inhibitor of osteoblastic cell functions.