Obtenção, caracterização físico-química e avaliação do efeito cicatrizante de um hidrogel de alginato contendo extrato de Calendula officinalis L.

Abstract

Chronic wounds such as diabetic, vascular and pressure ulcers require nursing care, frequent change of wound dressings and prolonged treatment. Despite the variety of products available on the market there is a need for the development of new, effective and low-cost wound dressings. Alginate is a natural polymer extracted from seaweed and widely used in the manufacture of wound dressings. Alginate hydrogels are used in autolytic debridement and for the treatment of dry and low to moderately exuding wounds. The incorporation of active compounds in alginate hydrogels can enhance the healing effect. Calendula officinalis L, popularly known as marigold, is a medicinal plant with antimicrobial, anti-inflammatory, healing and antiseptic properties. This work presents the development and evaluation of the healing effect of an alginate hydrogel containing marigold extract. The healing effect was evaluated on excisional wounds created on the back of female Wistar rats. Fifty ovariectomized rats were divided into two groups (n = 25) and lesions were treated with alginate hydrogel (group 1, control) or alginatemarigold hydrogel (group 2). The areas of the lesions were measured during 28 days. On days 2, 7, 14, 21 and 28 of the lesion, five animals from each group were euthanized and fragments of skin from the lesion site were removed for histological analysis. Hematoxylin and eosin stains were performed to quantify inflammatory infiltrate, assess angiogenesis and macrophage count. Picrosirius red analysis was used to compare the relative abundance of collagen types I and III fibers. The alginate-marigold hydrogel presented physicochemical and stability properties suitable for application in the treatment of wounds. Significant differences were observed on the 14th and 21st days between the groups in the wound retraction rates. Histological analysis showed that the alginate-marigold hydrogel modulated the inflammatory phase with a decrease in inflammatory infiltrate on days 14 and 21 and macrophages on the 21st day when compared to the control group. The analysis of collagen fibers showed that there was a decrease in type III fibers and an increase in type I fibers on the 14th day in lesions treated with alginate-marigold hydrogel, suggesting an improvement in the healing progression