Formaldehyde directly induces cytotoxicity in human lymphocytes through ROS formation, mitochondrial/lysosomal destruction and oxidative stress; analysis of the protective effects of crocin

Here we investigated the direct effect of formaldehyde, a major environmental and occupational pollutant, and cytoprotective potency of crocin as a natural compound against its toxicity in human lymphocytes, an important immune cell.For this purpose, human lymphocytes were isolated from peripheral blood and exposed to different concentrations of formaldehyde for 4 hours. Then, to investigate the protective potential of crocin, the human lymphocytes were simultaneously treated with its different concentrations in presence of formaldehyde. A set of biochemical and flow cytometric indices including cell viability, ROS production, mitochondrial membrane potential (MMP) collapse, lysosomal damage, malondialdehyde (MDA) and glutathione (GSH) levels, as indicator of oxidative stress were measured.The findings showed that formaldehyde significantly induced ROS formation, MMP collapse, lysosomal membrane destruction, lipid peroxidation and cytotoxicity. Our observations showed that simultaneous exposure of crocin with formaldehyde could not significantly reduce the toxicity parameters caused by formaldehyde.Overall, we observed that formaldehyde can cause direct toxicity via ROS formation, MMP collapse, lysosomal damages and oxidative stress in human lymphocytes and crocin with routine concentrations cannot reduce these toxicities. Therefore, reducing the toxicity of formaldehyde in lymphocytes by stronger antioxidant agents is suggested in future studies.