In vivo effects of systemic insulin-like growth factor-I alone and complexed with insulin-like growth factor binding protein-3 on corticosteroid suppressed wounds.

Glucocorticoids are known to decrease wound healing by inhibiting the inflammatory response and collagen synthesis. In patients on steroids requiring emergency surgery, a safe agent that can be administered systemically is needed to reverse the deleterious effects of corticosteroids. TGF-beta and PDGF work topically but are not candidates for systemic administration. IGF-I and IGF-I:BP-3 are logical choices for systemic administration to improve wound healing. Both have been found in our laboratory to repair the corticosteroid-induced defect in wound healing when applied topically; the IGF-I:BP-3 complex gave significantly better results than IGF-I alone. Therefore, we asked whether these agents administered systemically could reverse the impaired wound healing caused by corticosteroids and whether the IGF-I:BP-3 complex was superior. Sprague-Dawley rats 350 g had 4 Hunt-Schilling wire mesh wound cylinders implanted s.c. on the back. Depo-Medrol (8 mg) was given s.c. at the time of surgery. Experimental rats were given daily s.c. injections of IGF-I or IGF-I:BP-3 (supplied by Celtrix Pharm, Santa Clara, CA) in PBS and 0.1% rat serum albumin, pH 6.0. The groups were: vehicle; IGF-I 125 micrograms/d; IGF-I:BP-3 complex containing 125 micrograms IGF-I/d. On post-op. day 17, the tissue in the wound cylinders was harvested and dried at 37 degrees C. Dry weight, DNA, total protein, and hydroxyproline (collagen) contents were obtained by our published procedures. Wound cylinder dry weight, DNA, total protein and hydroxyproline were increased by IGF-I 250%, 340%, 200% and 205%, respectively, over controls.(ABSTRACT TRUNCATED AT 250 WORDS)