Exposure to a contaminated environment and its relationship with human health: Mercury effect on loss of functionality and increased oxidative stress of blood cells

Abstract

Recent findings indicate elevated levels of total Hg in the waters of the Lagoa Mundaú-Manguaba Estuarine Complex (CELMM, Maceió-AL, Brazil) and the biological fluids of fishermen that live near CELMM. This study assessed Hg levels in whole blood and the functionality, structure, morphology, and oxidative stress of blood cells from fishermen (n = 60) compared with control volunteers (n = 65). A systematic assessment was performed, and our results revealed increased Hg concentration in fishermen's blood. Erythrocyte functionality showed a 39 % decrease in O₂ uptake. For peripheral blood mononuclear cells (PBMCs), ROS generation demonstrated an 87 and 116 % increase in O₂^•- and H₂O₂ production, respectively, confirmed by fluorescence microscopy. Scanning electron microscopy showed increased roughness in the PBMCs membrane. Secondary oxidative stress markers revealed a reduction in the GSH/GSSG ratio and thiol content. MDA production increased by 89 %, while antioxidant enzyme activities showed a 159 and 22 % increase in SOD and CAT, respectively; otherwise, a depletion of 33 % in GPx. The metabolomic profile exhibited changes in essential amino acids for GSH formation, and energy pathways were modified. Finally, our data indicates that exposure to a polluted environment alters redox status, leading to compromised function and structure of blood cells.