[Nitrogen monoxide and oxygen radicals work contrarily on proliferation behavior of human fibroblasts]

Oxygen radicals and nitric oxide are involved in a variety of regulative processes especially with regard to inflammation, immunoregulation and regulation of the vascular tone. The aim of our study was to investigate the effects of both these highly reactive molecules on the proliferation of human fibroblasts. We therefore cultured WI38 cells under various culture conditions like exposure to oxygen radicals and endogenously produced as well as exogenously applied nitric oxide. Exposure of WI38 to oxygen radicals led to a reduction of cell proliferation. Similarly induction of endogenous nitric oxide production by cytokines induced an inhibition in cell proliferation. Interestingly exogenously applied nitric oxide increased proliferation rates of WI38 cells. These data could point to a functional role of oxygen radicals and nitric oxide in the regulation of fibroblast growth.