THE BENEFICIAL-EFFECTS OF RECOMBINANT HUMAN INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) ON WOUND-HEALING IN SEVERELY WOUNDED SENESCENT MICE

The effects of recombinant insulin-like growth factor I (rIGF-I) on wo und healing were tested using senescent and young BDF-1 mice, aged 108 weeks and 10 weeks, respectively, after inflicting a full thickness d ermal burn encompassing 15% of the body surface, a skin incision, 2 cm in length, was made in the back. A silicone tube containing a piece o f polyvinyl sponge was then implanted into a subcutaneous pocket in th e flank to collect body fluid. An osmotic pump was buried in the abdom inal subcutaneous tissue for the continuous infusion of rIGF-I, the co ntrol being treated with the solvent of IGF-I, physiological saline, o nly. The administration of IGF-I produced favorable effects on wound h ealing in the senescent mice, shown by enhanced tensile strength and a n elevated concentration in the hydroxyproline of the polyvinyl sponge content. The IGF-I-treated severely wounded senescent mice healed bet ter than their counterparts and their skeletal muscles contained more glutamine, Furthermore, they showed more enhanced cutaneous hypersensi tivity ton ards dinitrofluorobenzene than the controls, suggesting an enhanced grade of cellular immunity. There were no conspicuous differe nces between the two groups of young mice. These data map suggest the beneficial effects of rIGF-I on wound healing, especially in geriatric surgery.