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 wound healing were tested using senescent and young BDF-1 mice, aged 108 weeks and 10 weeks, respectively. After inflicting a full thickness dermal 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 of polyvinyl sponge was then implanted into a subcutaneous pocket in the flank to collect body fluid. An osmotic pump was buried in the abdominal subcutaneous tissue for the continuous infusion of rIGF-I, the control being treated with the solvent of IGF-I, physiological saline, only. The administration of IGF-I produced favorable effects on wound healing in the senescent mice, shown by enhanced tensile strength and an elevated concentration in the hydroxyproline of the polyvinyl sponge content. The IGF-I-treated severely wounded senescent mice healed better than their counterparts and their skeletal muscles contained more glutamine. Furthermore, they showed more enhanced cutaneous hypersensitivity towards dinitrofluorobenzene than the controls, suggesting an enhanced grade of cellular immunity. There were no conspicuous differences between the two groups of young mice. These data may suggest the beneficial effects of rIGF-I on wound healing, especially in geriatric surgery.