Peeling de fenol pontuado no tratamento do fotoenvelhecimento facial: estudo histoquímico e imuno-histoquímico

Abstract

Introduction: The physical appearance of the population has been increasingly taking on a significant role when we speak of general health and well-being. Thus, dermatological questions take on an ever greater medical significance. Chemical peels are an important therapeutic arsenal, with phenol peeling being classically recommended for treatment of skin lightening, attenuation of static wrinkles and facial skin flaccidity, requiring sedation in a hospital environment. In the punctuated technique, treatment can safely be done in an outpatient setting. Objective: investigating the mechanisms by which the technique proves effective when applied in a punctuated form and evaluating the changes in the collagenous extracellular matrix, elastic fibers and Type I and Type III collagen fibers, by automatic morphometry, and the increase of dermal mesenchymal cells, through immunohistochemistry. Methods: Facial skin biopsy blocks from female patients (n = 17), taken before and after treatment at the Dermatology Service of the Universidade Federal de Juiz de Fora University Hospital, were used. Patients were submitted to the protocol of five punctuated phenol peeling sessions. The histological sections were submitted to routine histopathological analysis (HE), histochemical analysis for elastic fibers (Verhöeff) and for Type I and Type III collagen fibers (picrosirius red), and immunohistochemical analysis for cells with positive vimentin expression in the dermis. Three patients were excluded because of insufficient material in the blocks for all of these stains. The data were expressed as simple arithmetic mean ± standard deviation, median, and shown in boxplot. Results: Upon comparing the collagenous extracellular matrix concentrations by HE and for elastic fibers (Verhöeff), there was an inverse relation in the histomorphometry, where of the eight patients with the lowest concentrations of collagen fibers in the group, six had the highest concentrations of elastic fibers. Of the six patients who had the highest concentrations of collagen fibers in the group, all of them had a concentration for elastic fibers below the group mean. Regarding the analysis of the relationship between Type III and Type I collagen fibers, there was an inversion of values due to the higher gain of Type I collagen fibers in relation to Type III collagen fibers. In the immunohistochemistry, 64. 28% of the patients (n = 9) presented increased mesenchymal cellularity. Conclusion: the results suggest that the clinical improvement in the treatment of facial photoaging with the proposed technique may be correlated with the greater balance between collagen and elastic material, with a higher production of Type I collagen fibers in relation to Type III collagen fibers, and with the increase of the number of mesenchymal cells in the post-treatment samples. In view of the results, we suggest that new studies be conducted, both clinical and experimental, to better elucidate the action mechanisms of the technique.