Augmentation of NO production and cytolytic activity of M phi obtained from mice irradiated with a low dose of gamma-rays.
The activation of macrophages (M phi) by low-dose irradiation (4cGy) was examined. The irradiated M phi were obtained from mice exposed to a low dose of gamma-rays. The addition of excess irradiated M phi suppressed more the concanavalin A-induced proliferation of splenocytes than that of unirradiated M phi. This was attributed to large nitric oxide (NO) production from irradiated M phi. In addition, low-dose irradiation augmented NO production and glucose consumption in M phi treated with interferon-gamma alone or interferon-gamma/lipopolysaccharide. Furthermore, low-dose-irradiated M phi showed a higher cytolytic activity against P-815 mastocytoma cells than unirradiated M phi, indicating that the NO production was involved in the activity. On the other hand, the M phi irradiated with a low dose in vitro did not enhance the NO production. These findings suggest that whole-body irradiation with a low dose of gamma-rays activates M phi indirectly and consequently enhances NO production from M phi, by which the self-defense systems such as the tumoricidal activity will be augmented.
Ibuki
Y
Y
Laboratory of Radiation Biology, Graduated School of Nutritional and Environmental Sciences, University of Shizuoka, Japan.
Goto
R
R
D000818:Animals; D003602:Cytotoxicity, Immunologic / Q000528:radiation effects; D005720:Gamma Rays; D008264:Macrophages / Q000276:immunology / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis*; D011829:Radiation Dosage; D014916:Whole-Body Irradiation
D009569:Nitric Oxide