Effects of the nerve growth factor on the survival and wound healing in mice with combined radiation and wound injury.

High dose of ionizing radiation could cause bone-marrow aplasia and delay wound healing. Nerve growth factor (NGF) has been demonstrated to play roles in wound healing and to affect the functional activities of mature immune and hematopoietic cells. In this study, we investigated the effects of NGF on survival and wound healing in mice with combined radiation and wound injury. Immunohistochemical analysis indicated that the expression of NGF decreased significantly at postwounding days 3, 5, 7, 10 and 14 in wounded tissues combined with total body irradiation of 5 Gy. NGF significantly increased the survival and migration of skin fibroblasts with the irradiation of 15 Gy in in vitro experiments. Intraperitoneal and topical applications of NGF increased the survival rate, peripheral white blood cells and bone-marrow nucleated cells; they also promoted wound healing and increased the cell number of fibroblasts and blood capillaries in granulation tissues. These results showed evidence that NGF could increase wound healing and promote survival in irradiated animals. This dual effect of NGF may provide a new tool for the treatment of radiation-combined injuries.