Pereira AFC, Torloni LBO, Lage R, Cascais LC, Andrade CC, Yamashita JT, Moreira F, Clerici SP, Eberlin S, Pinheiro ALTA, Pinheiro AS.
About 40-50% of total solar energy is infrared radiation, which penetrates deeply into the human skin reaching until subcutaneous layer. Studies have been emphasized effect of IR-A on photoaging and skin damage. Physiological doses of IRA lead to a disturbance of the dermal extracellular matrix by upregulation of collagen expression degrading enzyme matrix metalloproteinase-1 (MMP1) and decrease antioxidant enzyme activity. As such, the infrared induced cytotoxicity, DNA damage and oxidative stress. Thus, photoprotection of human skin against IR-A must be considered. Even though no specific chemical or physical filters direct against IRA are available, there is an alternative that can provide a sunscreen more broadly and favoring protection against photodamage, using antioxidant ingredients. In this study, we evaluated the in vitro effects of 17 susncreens formulations containing antioxidant ingredients in the prevention of infrared-A-induced damage in human skin fibroblasts through MMP-1 production. Our results demonstrated that irradiation with infrared A resulted in a significant up regulation of MMP-1 production up to 47 % in relation to non-irradiated. All sunscreen formulations produced significant reductions in the release of MMP-1 by human fibroblast in relation to IR-A group. The results can be expressed in percentage of protection of the test substances against infrared-A radiation considering the production of MMP-1 at baseline without exposure to the radiation. Under these conditions, sunscreens when incubated with cultures of fibroblasts promote up to 100% protection in the release of MMP-1. These sunscreens formulations are suitable for protection of IRA-induced MMP-1 up regulation in vitro in human dermal fibroblast cell culture. These effects can be attributed, at least in part, for the antioxidant ability of active ingredients present in the formulations. Although the precise mechanisms remain to be clarified, the results allow us to infer that the evaluated sunscreens exert a protective effect against the excessive increase in the synthesis of MMP-1 induced by infrared-A radiation - that reaches deeper into the skin - preserving the collagen that is a fundamental structure of tissue support, whose commitment contributes to skin aging process.