关键词: 黄曲霉毒素B1；液态乳；风险评估；人胚胎肝细胞（L-02细胞）；氧化应激

Abstract: This study investigated the cytotoxicity of aflatoxin B1 (AFB1) on normal human liver cell line L-02 and evaluated oxidative damage caused by AFB1 based on changes in cell proliferation rate, reactive oxygen species (ROS) and malondialdehyde (MDA) contents. The relative survival rate of the cells was determined by colorimetry using VC as a cytoprotectant. The extent of AFB1-induced apoptosis in L-02 cells as well as the underlying mechanism was assessed by changes in the cell cycle and cell apoptosis rate. The results showed that the AFB1 exposure concentration was determined as 40 μg/mL based on its half maximum inhibitory concentration (IC50) and VC concentrations for maximum cell viability ranged from 0.025 to 0.250 mg/mL. AFB1-induced cell damage was not attenuated at VC concentrations ≥ 0.5 mg/mL. ROS levels in the VC and VC + AFB1 groups were higher than in the control group but lower than in the AFB1 group, implying that VC can help reduce the MDA level in the cells and attenuate oxidative damage. Cell apoptosis and cycle analysis showed that AFB1 increased the percentage of apoptotic cells at the mid-late stage of apoptosis and that addition of VC inhibited the occurrence of apoptosis. Moreover, AFB1 induced cell cycle arrest in the G0/G1 phase and cell cycle parameters returned to almost normal after addition of VC.

Key words: aflatoxin B1 (AFB1); milk; risk assessment; normal human liver cell line L-02; oxidative stress