Aplicação tópica do hormônio do crescimento acelera a cicatrização de feridas na pele de camundongos

Abstract

The healing of skin wounds is a complex process involving biological events crossreactions between the cells of the epidermis and dermis involving cytokines, growth and modulation of extracellular matrix factors. In this context, the growth hormone ( GH ) has been appointed as an agent able of influencing molecular modulation and cellular aspects of wound healing, as seen in patients which have suffered severe burns and in transgenic animals to GH. On the other hand, it is known that high levels of GH in the circulation can cause changes in various organs of the body, and may also have implications in cancer. Thus, it is interesting to analyze the effect of topical treatment with GH in skin wounds in mice. For this study, Swiss mice, male and 6 months age, suffered injury in the skin after administration of anesthetic, where nine animals received GH at a concentration of 10⁻⁸ M, nine animals received GH at a concentration of 10⁻⁷ M, nine animals received PBS and nine others were treated with Bepantol. Macroscopic observations were made daily. The animals were euthanized on the 3rd, 7th and 14th day after treatment. Skin fragments were obtained and subjected to HE staining and Masson's trichrome for analysis of morphological aspects. Immunofluorescence was performed to detect the production of type I collagen. The blood vessels were detected from the immunoperoxidase labeling for the CD31 molecule. The results showed that topical treatment with GH, independent of the concentration used, accelerated in all periods analyzed, the closure of the wound area when compared to the group that received PBS. Histological analysis of the wound area after 3 days of treatment revealed the formation of a more diffuse inflammatory infiltration in the group treated with GH. After the 7th day of treatment we observed the formation of granulation tissue in all groups. However, in animals treated with GH the cell infiltrate was increased and diffuse while in the control group the infiltrate was also observed in the peripheral regions of injury. The Masson staining showed increased production of total collagen in animals treated with GH compared to control in all periods analyzed. This effect was corroborated by the expression of collagen type I. About vascular aspects, GH significantly increased the number of blood vessels in the area of injury when compared to the control group. Together, these results demonstrated that GH anticipated recruitment of inflammatory cells, deposition of collagen and the formation of blood vessels, contributing to the acceleration of tissue healing .!