Silicone sheeting decreases fibroblast activity and downregulates TGFbeta2 in hypertrophic scar model

Fibroproliferative disorders, which include hypertrophic scars and keloids, represent deviations from the normal process of wound healing. The fibrogenic cytokines have been associated with excessive scarring. It has been proposed that placing silicone in contact with hypertrophic scars may prove to be an effective form of treatment. This may be a result of downregulating fibroblasts and/or decreasing the fibrogenic cytokines. An in vitro model to study wound contraction is a fibroblast populated collagen lattice (FPCL). This study used FPCL as a method to study the effect of silicone sheeting on hypertrophic scar fibroblasts.

Fibroblast cultures were obtained and collagen lattices were prepared. Silicone sheeting was placed over the collagen matrix versus Saran wrap used as a treatment control. The amount of gel contraction was measured every 24 hours for five days. The supernatant obtained from the culture medium following completion of the FPCL portion of the experiment was then used in an immunoassay for TGFbeta2.

A statistically significant decrease in amount of FPCL contraction occurred between three of the four brands of silicone sheets used compared to untreated control or Saran wrap treated FPCL. The immunoassay for TGFbeta2 showed a statistically significant decrease with all four types of silicone sheeting.

FPCLs populated with burn hypertrophic scar fibroblasts exposed to silicone sheeting have decreased contraction compared to an unexposed control and Saran wrap treated control. In addition, TGFbeta2 is downregulated in the silicone exposed group. It appears that silicone sheeting may act by downregulating fibroblasts and decreasing fibrogenic cytokines.