COLLAGEN GENE-EXPRESSION AND WOUND STRENGTH IN NORMAL AND RADIATION-IMPAIRED WOUNDS - A MODEL OF RADIATION-IMPAIRED WOUND-HEALING

BACKGROUND. Poorly healing wounds result in significant morbidity post operatively. Numerous attempts have been made to study wound healing i n vivo to understand better the normal healing process and factors tha t impair healing. Animal models of wound healing have been developed t o evaluate wound healing in a systematic and controlled setting. Incis ional wounds are created in animals to mimic the surgical patient. The y may then be evaluated by a variety of methods for degree of healing. OBJECTIVE. To give insight into the mechanisms of wound healing impai rment, we developed a model of impaired wound healing in guinea pigs u sing radiation applied to the skin surfaces only. METHODS. Wound burst ing strength, a direct measure of the force required to burst apart he aling linear incisions, was measured. Collagen content, measured indir ectly as collagen gene expression, was measured. RESULTS. Significant reductions in wound bursting strength were noted after radiation admin istration. Collagen gene expression was decreased in wounds 7 days aft er radiation, but recovered to control levels 14 days after irradiatio n. Our model enables the inclusion of irradiated and unirradiated skin flaps within the same animal, thus eliminating intra-animal variation when comparing impaired and normal wounds. CONCLUSION. Wound bursting strength analysis, combined with techniques aimed at elucidating chan ges at the molecular level, provides a useful tool for the study of fa ctors that impair healing and potential treatments for resulting heali ng deficits.