Protective effects of polyvinylpyrrolidone-wrapped fullerene against intermittent ultraviolet-A irradiation-induced cell injury in HaCaT cells

Protective effects of dissolved molecular hydrogen against hydrogen peroxide-, hydroperoxide-, and glyoxal-induced injuries to human skin keratinocytes

Molecular hydrogen (H₂) is recognized as a gaseous antioxidant, and it is expected to ameliorate various disorders related to oxidative stress and inflammation. However, there are still many unclear points regarding its effectiveness in the skin. Therefore, the purpose of this study was to examine the protective effect of H₂ against ultraviolet (UV) irradiation-related stress injury in human epidermal HaCaT cells. We investigated the effects of H₂ against three types of UV-derived oxidative stress using human skin keratinocytes: hydrogen peroxide (H₂O₂)-induced oxidative stress, tert-butyl hydroperoxide (t-BuOOH)-induced lipid peroxidation stress, and glyoxal-induced carbonyl stress. Our results showed that H₂ exerted cytoprotective effects against stress induced by H₂O₂, t-BuOOH, and glyoxal. Furthermore, our results also revealed that H₂ suppressed H₂O₂-induced increases in intracellular peroxide and H₂O₂ levels, and suppressed the progression of lipid peroxidation. Taken together, our results demonstrate that H₂ can exert protective effects against oxidative stress-, lipid peroxidation-, and carbonyl stress-induced cellular injuries in human keratinocytes, partly mediated via suppression of intracellular oxidative stress and peroxide generation. Therefore, H₂ is expected to be utilized as an effective and attractive component in cosmetic formulations in the future.

EPR Technology as Sensitive Method for Oxidative Stress Detection in Primary and Secondary Keratinocytes Induced by Two Selected Nanoparticles

Exogenous factors can cause an imbalance in the redox state of biological systems, promoting the development of oxidative stress, especially reactive oxygen species (ROS). To monitor the intensity of ROS production in secondary keratinocytes (HaCaT) by diesel exhaust particles and thermoresponsive nanogels (tNG), electron paramagnetic resonance (EPR) spectroscopy after 1 and 24 h of incubation, respectively, was applied. Their cytotoxicity was analyzed by a cell viability assay (XTT). For tNG an increase in the cell viability and ROS production of 10% was visible after 24 h, whereas 1 h showed no effect. A ten times lower concentration of diesel exhaust particles exhibited no significant toxic effects on HaCaT cells for both incubation times, thus normal adult human keratinocytes (NHK) were additionally analyzed by XTT and EPR spectroscopy. Here, after 24 h a slight increase of 18% in metabolic activity was observed. However, this effect could not be explained by the ROS formation. A slight increase in the ROS production was only visible after 1 h of incubation time for HaCaT (9%) and NHK (14%).