Abstract

Environmental exposure to arsenite (As +3 ) is known to induce immunotoxicity. Natural killer (NK) cells are innate lymphoid cells act as professional killers of tumor cells. Our previous report indicated that 500 ppb As +3 drinking water exposure induced significant DNA damage in the NK cells of C57BL/6 mice. Myricetin is a plant-derived flavonoid known as a strong antioxidant. In this study, daily administration of myricetin at 20 mg/kg was found to alleviate the cell population decrease and DNA damage in the NK cells of BALB/c mice exposed to 500 and 1000 ppb As +3 via drinking water. Oxidative stress and poly(ADP-ribose) polymerase 1 (PARP-1) inhibition were induced by As +3 at 1 and 2 μM in isolated mouse NK cells in vitro , which were attenuated by 20 μM myricetin. The mitigatory effect of myricetin on the PARP-1 inhibition in NK cells treated with As +3 was also found to be the result of its prevention of the zinc loss induced by As +3 on PARP-1. Collectively, these results demonstrated, for the first time, that myricetin could protect NK cells from As +3 induced DNA through attenuating oxidative stress and retaining PARP-1 activity, indicating that myricetin may be utilized for the prevention of the immunotoxicity induced by As +3 in NK cells.