Effects of Formaldehyde on Cytotoxicity and Antioxidant Defense/Oxidative Stress Biomarkers in Hepatocytes Isolated From Rainbow Trout (Oncorhynchus Mykiss)

Abstract

Abstract: Formaldehyde (FA) is a widespread disinfectant in the aquaculture industry that is utilized in the treatment of diseases and control of external parasites in fish. Although numerous studies have investigated the toxic effects of FA, as far as is known, there has been no in vitro work characterizing its cytotoxic mechanism of action using fish cells in the literature. Therefore, herein, it was aimed to examine FA toxicity on hepatocytes that were isolated from rainbow trout (Oncorhynchus mykiss) in vitro. For this purpose, the cells were exposed to increasing concentrations of FA (0, 12.50, 50, 100, 200, and 400 µM) for 24 h. Next, the cytotoxic effects were evaluated via lactate dehydrogenase assay in addition to the use of antioxidant defense system markers, including the catalase (CAT), superoxide dismutase (SOD), glutathione S-tranferase (GST), glutathione peroxidase (GPx) activities and the glutathione (GSH) and malondialdehyde (MDA) levels. According to the obtained results, the FA caused small increases in the percentage of cytotoxicity with significant differences at a concentration of 50 µM and above. Moreover, significant decreases in the SOD, CAT, and GST activities and GSH content were determined. Meanwhile, the GPx activity showed remarkable increases. In addition, the MDA level was increased by the FA treatments. In conclusion, FA caused cytotoxicity by depressing antioxidant defenses and leading to oxidative stress in the hepatocytes. Considering these results, human and environmental health should be taken into account during its utilization and its unconscious usage should be avoided. © 2025 Elsevier B.V., All rights reserved.