FIGURE 3.

Inhibition of antioxidants in proton-exposed LE cells. A, proteins were extracted from 12-h post-irradiated and control LE cells, and 50 μg of total proteins was used to assay glutathione activity as described under “Experimental Procedures.” B, SOD activity was assayed by mixing SOD reaction buffer, xanthine, and nitro blue tetrazolium solution with 50 μg of proteins isolated from 12-h post-irradiated (different doses of protons) and control LE cells following the manufacturer's formula. The glutathione and SOD results are means ± S.D. of three independent experiments. C, protein extracts were prepared from 12-h post-irradiated (different doses) and control cells and analyzed for SOD-1 and -2 proteins using specific antibodies. β-Actin was used as an internal loading control. ns, nonspecific band.