Efeitos do calor induzido por luz visível sobre a pele e o reparo tecidual cutâneo de camundongos

Abstract

The role of heat induced by visible light on the skin and tissue repair remains unclear. Our goal was to investigate the heat effects on skin and cutaneous healing. Male mice were submitted to an excisional cutaneous lesion, divided into two groups (n=10/group) and exposed at 23°C or 43°C in a thermal chamber for 30 minutes for 13 days. On the 14th day after the injury, the animals were euthanized, lesions and samples of normal skin were collected and processed for analysis. In the skin, the heat induced by visible light increased the thickness of the epidermis, the dermis, the gene and protein expression of TGF-β. It increased the area of collagen fibers, decreased the gene expression of Col1a1 and the protein expression of type I collagen. Increased protein carbonylation, gene expression of Col3a1 and protein of collagen type III. It increased the area of elastic fibers, the gene expression of fibrillin-1 and elastin. In the cutaneous lesion, the area of the lesion increased on the 11th and 14th days after the lesion and the percentage of reepithelialized lesions decreased on the 14th day after the lesion. The epidermal gap length, the volume density of myofibroblasts and the number of macrophages were estimated. It increased the protein expression of type III collagen and MMP-1, decreased collagen type I and MMP-2 activity, increased the protein expression of fibrillin-1, MMP-12, TGFβ-1/2/3 and ERK. In conclusion, heat may have anti-aging effects on the skin, however, it delays the healing of skin lesions in mice.