NEUTROPHILS, IRON AND MICROCYSTIN: STUDY OF ENVIRONMENTAL TOXIC AGENTS AND OXIDATIVE STRESS IN AN IN-VITRO MODEL

IRIS CHIESA; FABIANA LAIRION; CLAUDIO CARVIA; CHRISTIAN SAPORITO; MARISA REPETTO

Mar del Plata

Congreso; 67º Reunión Anual de la Sociedad Argentina de Investigación Clínica; 2022

Sociedad Argentina de Investigación Clínica

Human polymorphonuclear cells (PMN) are involved in the resolution of infectious andinflammatory processes, in the regulation of spontaneous tumorogenesis and in thedevelopment of cancer. Excess inorganic iron (Fe 2+ ) and the presence of MC-LR/hepatotoxin(MC-LR) in drinking and recreational water are considered detrimental to human health andpredispose to inflammatory and neoplastic processes associated with PMN-induced oxidativestress (OS). Therefore, our aim is to characterize the damage of both antigens by detectingOS and cellular respiratory burst in PMNs exposed to different concentrations of Fe 2+ andMC-LR. Methodology: Enriched PMN fractions were obtained from venous blood of healthyvolunteers to assess OS and cellular respiratory burst (RB). Each sample was separated intoaliquots and incubated, one part with Fe 2+ and the other with MC-LR, at 37 °C for 15 minutes.OS was assessed by measuring spontaneous chemiluminescence (CL) of the cells with ascintillation photon counter, and oxygen consumption (OC) with a Clark-type oxygenelectrode at 37 °C, in basal condition or after activation (exposure to agonist for 15 minutes).In order to determine the effects of Fe 2+ and MC-LR on PMN function, increasingconcentrations were evaluated, Fe 2+ : 0, 6, 30, 300 µg/L and MC-LR: 0, 1, 25 µg/L. Results:The optimal cell concentration for assessing OS in PMNs was 8 x10 4 PMN/mL. OCdecreased 40% with 6 and 30 µg Fe 2+ /L (p<0.01) and 60% with 300 µg Fe 2+ /L (p<0.001), butCL increased 100% with 30 µg Fe 2+ /L (p<0.01). MC-LR increased OC 34% (1 µg MC-LR,p<0.05) and 60% (25 µg MC-LR, p<0.01) and CL 60% (1µg MC-LR/L, p<0.001) comparedto control. Conclusion: Fe 2+ does not activate RB mediated by NADPH oxidase in the rangeof concentrations allowed in water, however, it generates OS with the higher concentrationallowed. MC-LR generates RB in the allowed range of concentration, and OS at the lowerconcentration, suggesting that OS is involved in the toxic mechanisms.