RESUMO
Cellular senescence is a defense mechanism in response to molecular damage which accumulates with aging. Correspondingly, the number of senescent cells has been reported to be greater in older than in younger subjects and furthermore associates with age-related pathologies. Inter-individual differences exist in the rate at which a person ages (biological age). Here, we studied whether younger biological age is related to fewer senescent cells in middle-aged individuals with the propensity for longevity, using p16INK4a as a marker for cellular senescence. We observed that a younger biological age associates with lower levels of p16INK4a positive cells in human skin.
Assuntos
Envelhecimento/metabolismo , Envelhecimento/patologia , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Pele/citologia , Pele/metabolismo , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Contagem de Células , Senescência Celular/fisiologia , Células Epidérmicas , Epiderme/metabolismo , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Longevidade/fisiologia , Masculino , Pessoa de Meia-Idade , Envelhecimento da Pele/fisiologiaRESUMO
In a study of biomarkers of ultraviolet-A1 radiation (UV-A1)-induced skin damage, living skin equivalent cultures (LSE) were treated with the antioxidants hesperetin and quercetin-3-glucoside and irradiated with 25 or 50 J/cm2 UV-A1. Changes in the following biomarkers were measured; Interleukin 1-alpha (IL-1alpha), Heme Oxygenase-1 (HO-1), TdT-mediated dUTP nick end labeling (TUNEL) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). IL-1alpha and HO-1 were analyzed by real-time PCR, Western blot, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. TUNEL and 8-OHdG were determined by (immuno)histochemical techniques. Sections were stained with hematoxylin and eosin (H&E). UV-A1 induced keratinocyte and fibroblast vacuolation and nuclear pyknosis, intense TUNEL staining of fibroblasts and increased staining of cells and nuclei for 8-OHdG. Lesser or marginal increases in intensity followed staining for HO-1 and IL-1alpha. The IL-1alpha increase was confirmed by ELISA assays of the medium supernatants. Hesperetin and quercetin-3-glucoside reduced changes in H&E, 8-OHdG, TUNEL and IL-1alpha. Quercetin-3-glucoside reduced the amount of IL-1alpha in LSE media. These observations support the use of the selected biomarkers to monitor UV-A1 damage and provide evidence that dietary ingredients could reduce ultraviolet-A radiation-induced damage.
