Male and female rats with severe protein restriction present delayed wound healing

Abstract

Malnutrition remains a significant problem, not only in developing countries, but also in the developed world. The aim of this study was to investigate the effects of protein restriction on rat excisional cutaneous healing. Male and female rats (12 weeks old) were exposed to different degrees of protein restriction (23%, 12% (slight restriction), and 0% (severe restriction)) for 12 weeks. On week 9, a full-thickness excisional skin lesion was performed, and the lesion area was measured to evaluate wound contraction and re-epithelialization. Euthanasia was performed after 12 weeks, and the lesion and adjacent skin were removed, fixed in formalin, and embedded in paraffin. Sections were stained with hematoxylin-eosin, toluidine blue, picro-mallory, and sirius red, and were immunostained for α-smooth muscle actin. Animals (males and females) exposed to severe protein restriction (0% protein) presented impairment of wound contraction. Inflammatory cells were present in higher amounts in the protein-restricted groups than in the 23% group. Extracellular matrix was poorly deposited in the severely restricted group (0%), but only mildly disturbed in the slightly restricted group (12%). Neovascularization was disturbed in both restricted groups. Our study demonstrates that animals exposed to slight protein restriction present disturbed wound healing, but animals exposed to severe protein restriction present impaired wound healing.