Superoxide dismutase levels in canine marrow fibroblasts with elevated D0 values

The levels of the enzyme superoxide dismutase were compared in radioresistant and control fibroblasts from canine bone marrow aspirates. The D0 values of the resistant cells following in vitro irradiation with x-rays were significantly greater than the controls as measured by their proliferative response. Fibroblasts were grown to 80-90% confluency, harvested, sonicated and an extract of the 20,000 g supernatant prepared. Superoxide dismutase was measured using xanthine oxidase with hypoxanthine as substrate and luminol to detect the superoxide radical anion. Three sets of extracts were compared. No consistant differences were detected in activity between the resistant and control cells. 4 references, 1 table