Wound healing in X-irradiated mammalian skin

Certain parameters of wound healing were investigated in mouse skin given 950 rads and 3325 rads of X-irradiation at various times relative to wounding. Increased inflammation, delayed dermal regeneration, and delayed contraction were noted in all irradiated groups. The activation of surrounding hair follicles, a process that usually accompanies wounding in mouse skin, occurred earlier, over a shorter elapsed time, and over a greater area of skin in animals irradiated prior to wounding than in the controls or in those irradiated and wounded simultaneously. Epidermal mitotic activity in wounds made at the time of irradiation was initially depressed but recovered by the second postoperative day. Wounds in pre-irradiated animals gave an unexpected result. They responded with an immediate burst of mitotic activity without the usual 24-hr lag that was seen in controls. In the pre-irradiated specimens a substantial number of cells appeared to die after dividing.