Anais Brasileiros de Dermatologia (Apr 2007)
Efeitos do uso crônico da dexametasona na cicatrização de feridas cutâneas em ratos Effects of chronic use of dexamethasone on cutaneous wound healing in rats
Abstract
FUNDAMENTOS: Acredita-se que os glicocorticóides prejudiquem a cicatrização, causando decréscimo da proliferação celular, da neovascularização e da produção de matriz. OBJETIVO: Investigar os efeitos do uso crônico dos corticoesteróides na cicatrização de feridas cutâneas. MÉTODOS: Após injeções de dexametasona (0,1mg/kg/dia) por 30 dias, fez-se incisão no dorso de ratos e estudou-se a cicatrização no terceiro, sétimo e 14o dias. A resistência da cicatriz, a densidade do colágeno e a reação inflamatória foram avaliadas pela histometria. RESULTADOS: As cicatrizes do grupo tratado com dexametasona eram menos resistentes à tração em todos os tempos (p=0,008) e apresentavam menor densidade de colágeno. A do colágeno tipo III foi menor em todos os tempos estudados (pBACKGROUND: Glucocorticoids are believed to hinder healing process, causing decreased cell proliferation, neovascularization and matrix production. OBJECTIVE: To investigate the effects of the chronic use of corticosteroids on skin wound healing. METHODS: After daily injections of dexamethasone (0.1 mg/Kg) for 30 days, an excision was made in the dorsum of rats. Wound healing was evaluated at postoperative days 3, 7 and 14. Scar resistance, collagen density and inflammatory reaction were assessed by histometry. RESULTS: The scars of the dexamethasone-treated group were less resistant to traction in all days (p=0.008) and presented lower collagen density. Collagen III density was affected at all times (p<0.0001) and collagen I density was lower only on day 14 (p<0.0001). The inflammatory cell infiltration was less intense in the dexamethasone-treated group in the first two evaluations (p=0.001 and p=0.016), but there was no significant difference on day 14, (p=0.367). CONCLUSIONS: We observed decreased scar resistance and lower total collagen density in all periods studied. In the beginning of the process, low collagen III density was observed and later collagen type I density was also decreased. Reduced number of inflammatory cells was found in the first two evaluations.
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