Hidrogel cicatrizante a partir de hemiceluloses vegetais de Caesalpinea pulcherrima e proteínas laticíferas de Calotropis procera

Abstract

Calotropis procera (Ait.) R. Br. is well known for being a latcifers plant and for its medicinal properties. Its latex has already been used in traditional medicine in the treatment of dermis disorders. Scientific studies have shown that laticifers proteins isolated from C. procera have several pharmacological properties and their anti-inflammatory, antiseptic, analgesic and wound healing effects are reported. The aim of this work was to evaluate the effect of the CpPII protein fraction of C. procera on cicatricial process modulation in experimental wound models. For this, a hydrogel (Hg) was developed using natural hemicelluloses (galactomannans) from Caesalpinea pulcherrima, as excipient, and laticifers proteins (CpPII), rich in proteolytic enzymes as active principle. In the present study, laticifers proteins containing proteolytic activity (CpPII) or inhibited with iodoacetamide (IAA) were incorporated at different concentrations (w/v) in galactomannan hydrogels (Hemi) to obtain the following formulations tested: HgCpPII 0.2%, HgCpPII 0.5% and HgCpPII-IAA 0.2%. Male Swiss mice were used for in vivo tests (wound healing and dermal irritability) according to experimental procedures approved by the institutional ethics committee under number 64/2014. Tissue modifications and target mediators of cicatricial response were evaluated according to morphometric, biochemical, immunological and histological parameters in excisional wound models (1cm2). The results showed that the hydrogel formulations presented satisfactory quality after microbiological analysis, storage stability at 4ºC and dermal biocompatibility. Wounds treated with the CpPII fraction showed modulation of inflammatory mediators (MPO, NO, IL-1β, IL-6) and reduction of lipid peroxidation (MDA). The number of mast cells degranulated in the CpPII-treated animals increased significantly on day 14, and the mast cells degranulation in the group treated with 0.5% HgCpPII (p <0.05) was higher. There was also intense stimulation of the inflammatory and proliferative phase of healing process. Furthermore, fibroblasts activation and collagen deposition resulted in a significant increase in the rate of wound contraction as well as tissue re-epithelialization when compared to control groups (p <0.05). Wound healing assays with the CpPII fraction inhibited by iodoacetamide (20mM) showed that the latex pharmacological properties were not only associated with the presence of proteolytic activity proteins. The HgCpPII hydrogel did not induce dermal irritation and efficiently stimulated wound healing by acting on the different phases of the healing process. Hemicelluloses, initially proposed as a delivery vehicle for immunomodulatory proteins, were involved, at least in part, in modulating the process possibly acting as antioxidants. This study suggests a new application for plant hemicelluloses as vehicles using C. procera latex immunomodulatory proteins as useful substances in the treatment of wounds. However, further investigations are required for deeper exploration of the optimal composition in terms of fixation and absorption in the skin by the proposed formulation to be tested in other wound healing models.