Avaliação da Calendula officinalis L.na cicatrização cutânea de cães. Aspectos clínicos, histopatológicos e histoquímicos

Abstract

The research and the application of medicines with natural origin are being more developed and searched in order to treat several pathologies, such as for human beings as for animals. In the veterinary routine it is observed that the traumas involving dogs happens with a high percentual resulting in cutaneous losses of different degrees. In view of that, the present work had as objective evaluate the cicatrization process of cutaneous wounds treated topically with an test pomade composed with calendula and vaseline, through clinical, histopathological and histochemistry studies. For the study 18 male dogs, adults, medium weight of 10,9±2,8 Kg, without defined breed were used. They composed three groups (A, B and C) with six animals each and just differing in the experimental time, in other words, in group A, the evaluation lasted for seven days, in group B, 14 days and in group C, 28 days. In each animal were produced three lesions separated amongst themselves for approximately 5 cm, in the lateral thoracic area which were submitted to the following protocol treatment: calendula pomade, vaseline pomade and sodium chloride solution 0,9% (SF). The change in the wounds curatives and the clinical evaluation happened daily until the day stipulated for the biopsy, in other words, at the 7th, 14th and 28th day. The clinical parameters observed were: general state of the animal, bristling of the hair, edema, erythema, pain at touch, secretion, crust, granulation tissue, cicatricial contraction, contraction of the wound, reactions of cutaneous sensibility, easiness of application and adherence of the curative. Histopathological exams were accomplished by the hematoxilin-eosin coloration and the histochemistry through Masson trichrome and picrosirius red staining. In the results it was observed that to the 70 day the wounds treated with SF presented adherence of the gauze compress to the wound, very dry and thick crusts and dark and opaque red coloration; the one of the other groups were shown with an intensity color and shine. The ones treated with calendula and vaseline pomade demonstrated discreet presence of granulation tissue in the central area of the lesion and cicatricial tissue in the borders. To the 14th day the wounds that received calendula and vaseline were characterized by the presence of crust, granulation tissue filling and cicatricial tissue; the ones treated with SF presented a larger amount of exsudate considered inflammatory. The clinical evaluations of the wounds studied in the group of 28 days happened until the 18th day, because starting from this moment all wounds were scarred. In the 7th day of treatment the histopathological evaluation verified that the wounds treated with calendula pomade were not total reepithelized, the epithelium in the margins of the wound were hyperplasic, with deep epidermic crests and beginning of epithelial proliferation. The granulation tissue was differentiated with great amount of active fibroblasts in the collagen synthesis, macrophages and neoformed vessels. In this same period in the wounds treated with vaseline and sodium chloride solution 0,9% (SF)reepithelization were not observed. In the 14th day the wounds, independent on the instituted treatment, presented the hyperplasic epithelium in the border of the lesion and with formation of epidermic crests, besides the presence of crust in the bed of the wound. In the wounds treated with SF on the 14th day was observed the presence of congests vessels in the granulation tissue and still intense inflammatory exsudate determining a retard in the evolution of the cicatricial process in relation to the wounds treated with calendula and vaseline pomade. In the histopathological qualitative analyses staining with picrosirius the wounds evaluated to the 70 day, independent of the treatment, demonstrated the presence of collagen’s fibers with greenish coloration, considered as type III collagen fibers. In the evaluations accomplished at the 140 day was observed the presence of fibers with greenish coloration in smaller amount and red coloration in larger amount, besides presenting a more defined and evident organization pattern in the wounds treated with calendula, when compared with the ones treated with vaseline and SF, suggesting the presence of type I and III fibers collagens. To the 28 days, the lesions had predominance of collagens fibers of red coloration in the center of the lesion, suggesting the presence of type I collagen, the organization pattern was more defined characterizing a steady fiber, and the wounds treated with calendula pomade the ones that presented more organized structures. The clinical aspect and the organization of the cellular structures were shown more evident in cutaneous wounds treated with the Calendula officinalis L. pomade that turns the product an option for topical application in the cicatricial processes of the skin.