Effect of granulocyte-macrophage colony-stimulating factor on wound nitrite level in normal and irradiated rats

Ionizing radiation is frequently used alone or in combination with surgery to treat malignancy. However, its sequelae present clinical problems in the form of poor wound healing. Granulocyte-macrophage colony-stimulating fact or (GM-CSF) has been used for the local treatment of chronic-impaired wound s. We have developed a random flap model in normal and irradiated rats to i nvestigate the effect of GM-CSF on nitric oxide (NO) concentration during w ould healing. 30 male adult Wistar rats were divided into Group 1 (n = 10; controls with no irradiation and no GM-CSF); Group 2 (n = 10; RT, irradiati on, no GM-CSF); and Group 3 (n = 10; RT and GM-CSF, irradiation and GM-CSF) . The irradiated groups received 30 Gy to their skin. Three weeks later all the irradiated and normal rats received skin slaps. The NO level was estim ated indirectly from nitrite in postoperative tissue samples by using the G riess reaction (after reduction to nitrite). The nitrite levels in Group 1 rats were significantly higher than those in Group 2 during the early phase of wound healing (P < 0.05). There was also a significant difference betwe en nitrite levels of Group 2 and Group 3 (P < 0.05). These findings suggest that wound healing was delayed by if radiation and that the release of NO induced by GM-CSF improved wound healing in irradiated tissue. Med Sci Res 27:685-688 (C) 1999 Lippincott Williams & Wilkins.