EXOGENOUS TRANSFORMING GROWTH FACTOR-BETA-2 ENHANCES CONNECTIVE-TISSUE FORMATION AND WOUND STRENGTH IN GUINEA-PIG DERMAL WOUNDS HEALING BY SECONDARY INTENT

Abstract

The presence of transforming growth factor-.beta. (TGF-.beta.) at the site of acute injury, its ability to attract inflammatory and connective tissue cells, and its stimulatory effect on the deposition of connective tissue matrix combine to suggest that it may play a key role in the response to injury. The effect of exogenous TGF-.beta. form 2 on dermal wounds healing by secondary intent was investigated using a spone composed of collagen and heparin as a delivery vehicle. Longitudinal lenticular-shaped wounds on the dorsum of adult guinea pigs were treated at the time of wounding with delivery vehicle containing 0.5, 1, or 5 .mu.g of purified, bovine bone-derived TGF-.beta.2, and were compared with wounds that received vehicle only or were untreatd. At days 8 and 14 the amount of connective tissue in the wounds and the extent of epithelialization were determined by histomorphometric methods, and wound breaking strength was determined. At day 8, but not at day 14, wounds treated with 1 or 5 .mu.g of TGF-.beta.2 contained a significantly higher proportion of connective tissue than did wounds treated with vehicle only, and they also exhibited higher wound strength. No effect on wound size or re-epithelialization was detected. The observations provide evidence that a single treatment with exogenous TGF-.beta.2 delivered in collagen/heparin sponge vehicle can accelerate repair in guinea pig dermal wounds allowed to heal by secondary intent.