The Role of Nrf2 in the Antioxidant Cellular Response to Medical Ozone Exposure

Ozone (O-3) is a natural, highly unstable atmospheric gas that rapidly decomposes to oxygen. Although not being a radical molecule, O-3 is a very strong oxidant and therefore it is potentially toxic for living organisms. However, scientific evidence proved that the effects of O-3 exposure are dose-dependent: high dosages stimulate severe oxidative stress resulting in inflammatory response and tissue injury, whereas low O-3 concentrations induce a moderate oxidative eustress activating antioxidant pathways. These properties make O-3 a powerful medical tool, which can be used as either a disinfectant or an adjuvant agent in the therapy of numerous diseases. In this paper, the cellular mechanisms involved in the antioxidant response to O-3 exposure will be reviewed with special reference to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its role in the efficacy of ozone therapy.