Desenvolvimento e avaliação biológica de novo curativo à base de quitosana e papaína como alternativa para o tratamento de úlceras em diabéticos

Abstract

Healing is a complex and dynamic event that aims to restore tissue integrity, but a possible intense inflammatory response can delay and hinder the success of its treatment. Chronic wounds are a public health problem, especially when associated with a risk group such as diabetics, becoming a major clinical challenge. Papain is an enzyme extracted from papaya (Carica papaya) with healing properties, and is widely used in the chemical debridement of conical wounds, but its use in high quantities or doses brings limitations both in its application. Chitosan is a copolymer obtained from natural sources and serves as a support for the immobilization of enzymes to increase their activity. The present study hypothesizes the possibility of obtaining chitosan membranes containing papain in different proportions for the first time and that this biological device improves the activity of the enzyme, enhancing the healing process. The general objective is to develop and evaluate the efficacy of biological dressings based on chitosan and papain in diabetic skin wounds, which may contribute to a new therapeutic option for the treatment of chronic wounds. For this, chitosan membranes containing different concentrations of papain (Ch / Ch Pap 2.5% / Ch Pap 5%) were obtained by the solvent evaporation method, the devices were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), absorption spectroscopy in the infrared region with Fourier transform (FTIR) and thermal analysis (DSC and ATG/DTG). Other studies included pH determination, swelling study, wettability, tensile assay, quantitative analysis, enzyme activity, in vitro enzyme release, and cytocompatibility and biocompatibility profile. The healing effect was evaluated in the in vivo model in Swiss mice and lesions were observed in groups of 7 and 14 days. The membranes presented characteristics suitable for their use, such as transparent and rough appearance and mechanical properties. Papain was successfully incorporated, the physicochemical properties demonstrated electrostatic interactions between papain and the copolymer, with pH between 7.1 and 7.5 The biodressing showed cytocompatibility and biocompatibility, which increased the enzymatic activity of free papain by 250 times. In vitro release indicated that the membrane modulated papain release in a controlled manner, adjusted by Higuchi's kinetic model. The in vivo analyses performed showed re-epithelialization, fibroblasts and thickening of the epithelium that help in the healing process in a significant proportion in the groups treated with the papain membrane 2.5% and 5% compared to the groups without treatment. Ch Pap 5% reduced wound size and inflammatory infiltrate compared to control animals or chitosan alone. Also, 5% papain increased the number of fibroblasts on day 7 and epithelium thickness on day 14 of the experimental model. The evaluated parameters showed that the chitosan membrane with 5% papain improved healing in diabetic mice. The experimental results corroborate the hypothesis of the study, membrane systems with papain have the potential for effective bioactivity, being a promising alternative for the use of wound closure and, due to its prolonged release, revealing a potential beneficial effect in the treatment of chronic wounds.