Effects of sunscreens in the protection of infrared radiation-induced MMP-1 in human dermal fibroblast
Author: Samara Eberlin
Published at: September 21, 2015
23rd IFSCC Conference (International Federation of Societies of Cosmetic Chemists), Zurich, 21-23 September, 2015.
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 the subcutaneous layer. Studies have emphasized the effect of IR-A on photoaging and skin damage. Physiological doses of IR-A lead to a disturbance of the dermal extracellular matrix by upregulating the collagen-degrading enzyme matrix metalloproteinase-1 (MMP-1) and decreasing antioxidant enzyme activity. As such, infrared induces 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 directed against IR-A are available, there is an alternative that can provide broader sunscreen protection using antioxidant ingredients. In this study, we evaluated the in vitro effects of 17 sunscreen 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 upregulation of MMP-1 production, up to 47% in relation to non-irradiated controls. All sunscreen formulations produced significant reductions in the release of MMP-1 by human fibroblasts compared to the IR-A group. The results can be expressed as a percentage of protection provided by 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, promoted up to 100% protection in the release of MMP-1. These sunscreen formulations are suitable for protection against IR-A-induced MMP-1 upregulation in vitro in human dermal fibroblast cell culture. These effects can be attributed, at least in part, to the antioxidant ability of the 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 - which reaches deeper into the skin - preserving collagen, a fundamental structural component of tissue support, whose damage contributes to the skin aging process.