Prevention of necrosis in ischemic skin flaps using hydrogel of Rhizophora mangle

Necrosis in ischemic cutaneous flaps (ISF) is a type of surgical failure more feared among surgical complications. Currently, synthetic drugs are applied during the treatment of necrosis in ISF and although several substances show improvement in viability, some require application at high systemic doses, which can produce important side effects. Therefore, the search for natural substances with fewer side effects is constant. The use of medicinal plants that stimulate angiogenesis is commonly mentioned in previous studies and in this case Rhizophora mangle L. (R. mangle) highlights that among its main compounds have tannins and flavonoids that are very chemically reactive in various biological activities. This study aimed to associate a natural hydrogel to the 5% extract of R. mangle and to evaluate its potential in the prevention of tissue necrosis in distal portions of ISF in rats, using the model proposed by Macfarlane, et al. (1965).

Ischemic skin flaps were made in the thin dorsal skin area of 28 Wistar rats and divided into 4 groups, group A: received only saline, group B where the aqueous extract of R. mangle was applied, group C received the 1.5% hydrogel of xanthan gum (XG) + placebo and group D was applied the hydrogel associated with 5% R. mangle extract. Morphometric analyses of the areas of tissue necrosis were performed from photographic records using the software Photoshop® and ImageJ®. In addition, 5 photomicrographs were taken from each histological sample of each animal for histomorphometric analysis that obtained the count of fibroblasts and blood vessels.

The mean percentage of necrotic areas was: group (A) - 50,66%, group (B) - 40,49%, group (C) - 37,44% and group (D) - 34,25%. The statistical analysis, using the Kruskal-Wallis test, showed a significant difference (p < 0.001).