Descrição da ação cicatrizante e toxicidade do extrato aquoso de Psidium guajava L. goiabeira em ratos wistar

Abstract

The increase of chronic diseases and estimates indicate that 300 million people will have diabetes in the world by the year 2025. This leads to a scenario with a high wound prevalence, being therefore essencial to improve the protocols for the treatment of skin lesions with pathological disturbances like these. The goal of this research is to describe the healing activity and toxicity of the aqueous extract of Psidium guajava in diabetic rats. The treatments were topical and oral in 4 groups of animals for the test of cicatrization (cutaneous lesions) and toxicity respectively: (I) non diabetic rats treated with the extract (0.2 g/mL); (II) non diabetic rat without treatment; (III) diabetic rats treated with the extract (0.2 g/mL) and (IV) diabetic rats without treatment, for the cicatrization tests. And, (I) rats treated with water; (II) rats treated with 100, 200 and 400 mg/KG, for the toxicity tests. It was performed histological, morphometric, histochemical and immunohistochemical tests for the cicatrization study, and histopathological, histochemical, biochemical and morphometric tests for the toxicity study. It was observed statistically significant keratinization in the animal groups I, II and III only. In the animals treated with the extract it was found the presence of numerous macrophages and giant cells. In the lesions of diabetic animals without treatment the concentration of collagen was smaller, and the rate of healing was higher by the 14 th day for the animals treated with the extract when compared to the other animals. The serum levels of enzymes Alanine ALT, AST, urea, creatinine and albumin were elevated in the animals treated with 400 mg/Kg. In the liver of the animals treated with 400 mg/Kg we evidenced a congestion of the portal vein, centrilobular and sinusoid capillaries. In the kidneys, with the same treatment, we observed the presence of areas with proliferative glomerulonephritis. The liver morphometry revealed a significant reduction of the lobular parenchyma and increase of the non lobular parenchyma in the animals treated with 400 mg/Kg as well as a significant glomerulus increase in diameter and volume , besides the diameter and volume of the Bowman capsules in the kidneys of animals treated with the same dosage. In the biochemical evaluation for glycogen there was a significant reduction in the liver of animals treated with 400 mg/Kg in relation to the others, which represents greater disadvantage with the use of such dosage, fact which does not occur in significant number for the other dosages, allowing therefore the recommendation of the crude extract of P. guajava as a promising phytotherapic asset.