Oxidative Stress Induced by Iodoacetamide (an Emerging Disinfection By-Product) on Hepg-2 Cells

Iodoacetamide (IAcAm) is a type of emerging nitrogenous disinfection by-products (N-DBPs) with high health risk. Up to now, several studies have been carried out about the toxicity of IAcAm, but the study on oxidative damage of IAcAm on human cells was not available. In this study the oxidative stress and damage induced by IAcAm on HepG-2 cells were investigated. Results showed that superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity exhibited a decreasing trend but Nrf-2 and GCLC (mRNA and protein level) generally appeared an increasing trend with the increase of IAcAm concentration, suggesting that IAcAm exposed cells produced excessive ROS and initiating the compensation mechanism of Nrf2 to deal with oxidative stress. Malonaldehyde (MDA), an index for oxidative damage, had no obvious change at 24h (p>0.05) but significant increased at 48 h (p<0.05). This result indicated that HepG-2 cells could protect themselves from ROS attack by consuming antioxidant enzyme (e.g., SOD and GSH-Px) and up regulating the genes related antioxidation after 24h exposure of IAcAm, yet at 48h, antioxidant defense system can no longer prevent oxidative damage of ROS, causing severe damage of lipid membrane.