PLATELET-DERIVED GROWTH-FACTOR AND WOUND CONTRACTION IN THE RAT

This experiment was undertaken for three purposes: (1) to determine a dose-response curve of acute steroid inhibition of wound contraction i n the rat; (2) to confirm the results of our preliminary study that pl atelet-derived growth factor (PDGF) enhanced wound contraction in acut ely steroid impaired rats; and (3) to examine the histology of the PDG F-treated wounds. To determine the dose-response of acute steroid inhi bition of wound contraction, the rats were suppressed with daily doses of methylprednisolone and wound contraction was measured, Results dem onstrated that significant glucocorticoid-induced inhibition of wound contraction begins with daily methylprednisolone doses of 2.0 mg/wound /day or 6.7 mg/kg/day. In an effort to confirm the results of our prev ious study of the effect of PDGF on wound contraction in acutely stero id-impaired rats and to study the histology of the PDGF-treated wounds , rats were suppressed with methylprednisolone or hydrocortisone and a dministered daily topical doses of rPDGF-BB. Wound contraction measure ments revealed no improvement in the amount or rate of wound contracti on. Histologically, the wounds were all very similar in the patterns o f cellularity, granulation tissue maturity, collagen content, and epit helial migration, We have clarified the dose response of acute steroid inhibition of wound contraction in rats, data previously unavailable, and have concluded that PDGF in reasonable doses does not improve wou nd contraction in steroid-impaired rats nor does it alter the histolog y of the wounds. (C) 1995 Academic Press, Inc.