Mamy Honda Igarashi, Sheila Gomes da Silva, Maurizio Mercuri, Gustavo Facchini, Gustavo Henrique da Silva, Ana Lúcia Tabarini Alves Pinheiro, Samara Eberlin.
Glycolic acid (GA) is the most commonly alpha-hydroxy acid peel used in dermatological practice. GA has several indications, such as acne, acne scars, melasma, postinflammatory hyperpigmentation, photoaging, and seborrhea. GA targets the corneosome by enhancing breakdown and decreasing cohesiveness, causing desquamation. In addition to this keratolytic action, GA has anti-inflammatory and antioxidant properties. The nanoencapsulation of active ingredients is a very promising approach to the development of nanocosmetics and nanomedicine. Modern encapsulation methods protect against premature degradation, increase efficiency, specificity and targeting capacity, in addition to reducing the toxicity associated with active ingredient. The purpose of this study was to evaluate the effects of two cosmetic cosmetic formulations containing free and nanoencapsulated GA on epidermal and dermal thickness and collagen production. Human skin explants, obtained from elective plastic surgery, were treated with cosmetic formulations containing free (GA-F) and nanoencapsulated (GA-N) glycolic acid for a period of 72 hours. Explants were submitted to histological procedures for immunofluorescence of procollagen type I and to measure the thickness of the epidermis and papillary dermis using hematoxylin-eosin staining. Skin cultures treated with the formulation containing GA-N showed a greater number of dermal papillae as well as greater amplitude of them, when compared to the control group. This result is corroborated by the measurement of the thickness of the epidermis and papillary dermis, which presented increases of 34.64% and 44.59%, respectively, in relation to the control group (P<0.001). In contrast, the formulation containing GA-F, in addition to not changing the thickness of the epidermis, promoted a significant decrease in the thickness of the papillary dermis. In line with these results observed in the dermis, the formulation containing GA-N was able to significantly stimulate the production of procollagen type I by 47.13% (P<0.01), when compared to baseline control. On the other hand, the formulation containing GA-F did not promote changes in the synthesis of type I procollagen. The results on the synthesis of type I procollagen and thickness of the epidermis and papillary dermis demonstrated that the nanoencapsulation of GA presents superior and statistically significant results in comparison to the free form. These data allow us to infer that this nanocosmetic formulation has a beneficial effect on fundamental structures supporting the skin tissue, whose impairment contributes to the premature aging process.