Aging and exposure to environmental factors can cause oxidative stress and chronic inflammation in the skin, leading to disorders like dermatitis and cancer. Oleanolic acid (OA), a natural triterpenoid compound found in plants like Olea europaea, is known for its antioxidative and anti-inflammatory properties, making it a potential solution for mitigating oxidative damage. Vasarri, et al., aimed to deepen the understanding of OA’s cytoprotective effects on human keratinocyte (HaCaT) cells under oxidative stress induced by tert-butyl hydroperoxide (tBHP).
Methods
HaCaT cells were pre-treated with OA and then exposed to tBHP to induce oxidative stress. Cell viability was assessed using an MTT assay, while intracellular reactive oxygen species (ROS) levels were quantified using a fluorescent probe. Nitric oxide (NO) production was measured using the Griess reaction. Western blotting and super-resolution confocal microscopy were used to analyze protein expression and localization.
Key Findings
•Cell Viability and Oxidative Stress: OA pre-treatment significantly improved cell viability and reduced intracellular ROS levels in HaCaT cells exposed to tBHP.
•iNOS Expression and NO Release: OA inhibited inducible nitric oxide synthase (iNOS) expression and subsequent nitric oxide release, indicating a modulation of inflammatory responses.
•Nrf2/HO-1 Signaling Pathway: While tBHP activated the Nrf2/HO-1 signaling pathway, OA did not enhance this response, suggesting that OA exerts cytoprotective effects through mechanisms independent of Nrf2 activation.
•MAPK Pathway: OA pre-treatment did not change the levels of phosphorylated ERK and p38, suggesting that OA’s antioxidative protective role is independent of the Nrf2 pathway.
This research demonstrates the protective effects of oleanolic acid on human keratinocytes against oxidative stress. The novelty of this research lies in its suggestion that OA operates through pathways distinct from Nrf2 and MAPKs, paving the way for new therapeutic strategies aimed at improving skin health against oxidative stress. Further research could explore OA’s specific mechanisms of action and its potential applications in preventing and mitigating oxidative damage in the skin.
Link to the study: https://www.mdpi.com/1424-8247/18/2/238
