Regulation of Proliferation of Mouse Bone Marrow-derived Mast Cells by Activated Fibroblasts

Nitric oxide (NO) is synthesized by various cells involved in inflammatory reactions and may then act on mast cells. In the present work, we attempted to clarify the role of this molecule on the proliferation of mouse bone marrow derived-mast cells (BMMC). Swiss 3T3 fibroblastsproduced nitrite ($NO_{2}$) and nitrate ($NO_{3}$) upon treatment with interferon ${\gamma}$(IFN-${\gamma}$). This formation was dependent of L-arginine and could be inhibited by the -L-arginine analogue $N^{G}$-monomethyl-L-arginine ($N^{G}$MMA). The effect of IFN-g was drastically invreased by cotreatment with tumor necrosis factor g(IFN-g). BMMC were maintained in vitro for as long as 30 days when cocultured with Swiss 3T3 fibroblasts. coculture with $N^{G}$MMA, significantly increased the number of BMMC. These results indicate that NO involves the inhibition of proliferation of BMMC when cocultured with Swiss 3T3 fibroblasts.