Hyperbaric Exposure and Oxidative Stress in occupational activities (HEOxS): the study protocol

Background: Hyperbaric exposure (HE) is proven to be a stressor to several mechanisms in living cells. Even if after homeostasis restoration, harmful effects are expected, in particular a presence of free radicals. These latter are the stimulus to negative phenomenon as inflammation or cancer. In Italy, with 7500 km of sea shores, a large quantity of workers is exposed to HE during occupational activities. A deep knowledge of HE and bodily effects is not well defined; hence a multidisciplinary assessment of risk is needed. To detect one or more indicators of HE a research group is organised, under the INAIL sponsorship. The research project focused on the oxidative stress (OxS) and this paper details on the possible protocol to estimate, with a large amount of techniques on several human liquids, the relationship between OxS and HE. Specific attention will be paid to identify confounding factors and their influence. Methods: Blood and urine will be sampled. Several lab techniques will be performed on samples, both targeted, to measure the level of well-known biomarkers, and untargeted.  Regard the formers: products of oxidation of DNA and RNA in urine; inflammation and temperature cytokines and protein carbonyles in blood. Untargeted evaluation will be performed for a metabolomics analysis in urine. Confounding factors: temperature, body fat, fitness, allergies and dietary habits. These factors will be assessed, directly or indirectly, prior and after HE. The final scope of the project is to determine one or more indicators that relates to HE in hits twofold nature: depth and duration. Conclusion: The relationship between OxS and HE is not deeply investigated and literature proposes diverging results. The project aims to define the time dependence of biomarkers related to OxS, to rise knowledge in risk assessment in workers exposed to HE.