Estudo dos marcadores bioquímicos na pele humana devido a fotoexposição crônica por Espectroscopia Raman

Abstract

Skin is an epithelial system that differs from other tissues because is in direct contact with the external environment, which is considered essential for life. Excessive exposure to solar radiation leads to a significant reduction in elasticity, atrophy, excessive pigmentation, dryness, appearance of wrinkles, thickening of the skin, degeneration of collagen and elastin, development of hyperchromias, telangiectasias and accentuation of the process of aging. Some studies have used optical methods in the study of the structural differences of the skin for the most varied ethnic origins and under the action of different treatments. micro-Raman spectroscopy technique in vivo and in vitro has enabled the identification and characterization in real time of biochemical changes resulting from the degenerative processes of living tissues. In addition to its high sensitivity and specificity, the technique provides the chemical fingerprint of the studied sample. The first part of this study was the validation of the technique, in order to prove the sensitivity and specificity of the Raman microscopy technique for skin applications. The results found in the validation phase of the technique, corroborate with the studies carried out by other authors, where they present the Raman microscopy technique as a sensitive analysis tool for chemical changes on the skin. After the good results obtained on the validation phase, the second part of this work was carried out, characterizing the chemical differences between the study groups, individuals with high and low sun exposure. In this part of the study, the samples were separated into two groups, one with high sun exposure and the other with low sun exposure. The results obtained after multivariate statistical analysis, showed spectral differences in the stratum corneum, epidermis and dermis layers. For all photoexposed groups and in all layers, conformational changes in lipids and proteins were observed, impairing the protective barrier function in the stratum corneum, affecting ceramides in the epidermis and type I collagen in the dermis. Also, in the photoexposed groups, changes in phenylalanine were observed in the layers of the stratum corneum and epidermis. The proline-hydroxyproline peaks were identified as suitable for assessing intrinsic versus extrinsic aging, and the regions of amide I and III can be used for photoaging evolutionary studies in the dermis layer. This study reveals the potential of the Raman spectroscopy technique as an alternative, fast and reliable method to assess biochemical changes in the skin related to continuous sun exposure.