Estabelecimento de modelo experimental para avaliação de alterações morfológicas e da pele de ratos wistar após aplicação de preenchedores: efeito do ácido hialurônico e da policaprolactona

Abstract

BACKGROUND: The demand for aesthetic treatments for facial contouring has driven the development and application of soft tissue filling agents. In this context, substances that restore lost skin volume and facial contour are highlighted. Polycane (PCL), a biodegradable polymer, has been used to improve the dermis, especially on the face, as it is a compact and compact polymer, in addition to accommodating compact spaces. Hyaluronic acid (HA) has emerged as the most used filling agent to restore tissue volume, in addition to hydrating and lubricating tissues. OBJECTIVES: The present work aims to establish an experimental model to investigate morphological changes in the skin of Wistar rats in response to filling agents and to understand the mechanisms of action of HA (Juvederm Voluma®) and PCL (Ellansé®). MATERIALS AND METHODS: The subcutaneous area of the back of Wistar rats was the recipient area of biomaterials, represented by PCL and AH. The animals were euthanized at 30 days or 60 days and samples of treated and untreated skin (NAIVE) were removed for histological and immunohistochemical evaluation for IBA-1, TGF-b and FGF. Analysis of type I and type III collagen deposition and angiogenesis was performed. RESULTS: HA appeared as an amorphous and basophilic material, interspersed with connective tissue bundles with discrete capillary proliferation. The skin fragments with PCL showed intense cell proliferation, nuclear aggregates with the presence of foreign body giant cells and greater capillary proliferation when compared to the AH group. A greater number of vessels was observed in the AH and PCL groups in relation to the NAIVE, however, there was no significant difference in the vessels between the groups studied. A significant increase in the fibroblast and fibrocytes count was observed in the skin fragments inoculated with HA and PCL in relation to the skin without filler. The number of fibroblasts was significantly higher in the PCL group when compared to the HA. The PCL group showed higher immunostaining for IBA-1 and TGF-b compared to the NAIVE and AH groups. Collagen deposition was observed in the treated groups, especially type III collagen, in the PCL group when compared to the HA. CONCLUSION: Our morphological findings demonstrate the stimulation of fibroblast activity and a related active regeneration of connective tissue, with increased vascular proliferation and expression of markers related to tissue proliferation, mainly related to the PCL group.