CYTOKINE MESSENGER-RNA CHANGES DURING THE TREATMENT OF HYPERTROPHIC SCARS WITH SILICONE AND NONSILICONE GEL DRESSINGS

BACKGROUND. Treatment of hypertrophic scars can be difficult for both patients and physicians. Silicone-containing gel dressings have been r eported to be an effective alternative treatment for hypertrophic scar s, yet the mechanism of action of these dressings is unknown. OBJECTIV E. TO determine whether silicone is an essential factor in the treatme nt of hypertrophic scars and investigate the effects of occlusive dres sing therapy on the expression of key wound healing mediators. METHODS . A pilot paired comparison, nonrandomized study was conducted compari ng a silicone gel sheeting (Silastic [SGS]) with a hydrogel dressing ( ClearSite). The effects of the dressings were compared side by side in the treatment of 15 hypertrophic scars at both the clinical and molec ular levels through the use of reverse transcriptase/polymerase chain reaction to evaluate effects on the expression of interleukin 8 (IL-8) , basic fibroblast growth factor (bFGF), granulocyte-macrophage colony -stimulating factor (GMCSF), epidermal growth factor (EGF): transformi ng growth factor beta (TGF-beta), and fibronectin. RESULTS. Comparable clinical improvement of the hypertrophic scars was obtained with both dressings. Treatment of hypertrophic scars resulted in increased mean levels of IL-8, bFGF, and GMCSF mRNA; while mean TGF beta and fibrone ctin mRNAs decreased after treatment with both dressings. Comparison b etween the two dressings revealed significant changes in IL-8 and fibr onectin mRNA levels after treatment with ClearSite, while only fibrone ctin changes were significant after treatment with SGS with respect to normal skin. Only ClearSite induced significant changes in IL-8 and b FGF levels when untreated scars were compared with posttreatment lesio ns, suggesting that the hydrogel augments collagenolysis via promotion of inflammation. CONCLUSIONS. This study demonstrates that silicone i s not a necessary component of occlusive dressings in the treatment of hypertrophic scars. The pathogenesis of hypertrophic scars is further elucidated by demonstrating that there is molecular evidence for exte nsive connective tissue remodeling occurring during occlusive dressing therapy. (C) 1996 by the American Society for Dermatologic Surgery, I nc.