Superoxide anions mediate proliferative response in cardiac fibroblasts.

The study was undertaken to examine whether superoxide anions mediate a proliferative response in cardiac fibroblasts. Cardiac fibroblasts isolated from newborn Wistar rats were exposed to superoxide anion generating system (hypoxanthine + xanthine oxidase) and its effect on cell growth was assessed. A stimulatory response on fibroblast proliferation was observed. The proportion of proliferating cells increased within 3 h of treatment compared to the control and the cell density after 96 h of exposure remained significantly high (P < 0.0005). Inclusion of antioxidants neutralised the stimulatory response, fortifying the role of superoxide anions in cell proliferation. This observation indicates that superoxide anions can mediate a fibrotic reaction in the cardiac tissue.