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Reduction of Scarring by Silicone in the Rabbit Ear Model
Author(s) -
Tandara Andrea A.,
Kloeters Oliver,
Mustoe Thomas A.
Publication year - 2008
Publication title -
wound repair and regeneration
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.847
H-Index - 109
eISSN - 1524-475X
pISSN - 1067-1927
DOI - 10.1111/j.1067-1927.2005.130215f.x
Subject(s) - scars , silicone , hypertrophic scar , hypertrophic scars , epidermis (zoology) , chemistry , in vivo , pathology , medicine , anatomy , dermatology , biology , microbiology and biotechnology , organic chemistry
Hypertrophic scars can be reduced by application of silicone dressing; however, the detailed mechanism of silicone action is still unknown. It is known that silicone gel sheets cause a hydration of the epidermal layer of the skin. An in vitro coculture experiment has shown that hydration of keratinocytes has a suppressive effect on the metabolism of the underlying fibroblasts resulting in reduced collagen deposition. We tested the hypothesis that silicone gel sheeting in vivo has a beneficial effect on scar reduction by a reduction in keratinocyte stimulation, with a resulting reduction in dermal thickness. Silicone adhesive gel sheets were applied to scars in our rabbit ear model of hypertrophic scarring 14 days post wounding for a total of 14 days. Scarring was measured in this model by the Scar Elevation Index (SEI), a ratio of the scar height over normal skin, and the Epidermal Thickness Index (ETI), a ratio of the epidermal height of the scar over normal epidermis. Ultrastructural changes were investigated using electron microscopy (EM). SEIs were significantly reduced after only 2‐week applications of silicone gel sheets versus untreated scars (1.18 ± 0.05 vs. 1.45 ± 0.09, respectively; P < 0.05)– corresponding to a 48.8% reduction of scar hypertrophy. The epidermal layer in scars was in general thicker than in unwounded skin. However, ETIs of untreated scars increased by 103% versus 71% after silicone gel treatment – corresponding to a significant reduction of epidermal thickness by 24.4%. EM showed a basal layer in untreated scars that was very different than normal skin with many vacuoles at the basement membrane level, while silicone gel‐treated scars had a basal cell layer which resembled unwounded epidermis. Our findings demonstrate that 2 weeks of silicone gel application at a very early onset of scarring reduces dermal thickness which appears to be due to a reduction in keratinocyte stimulation. These findings are consistent with our coculture results.