Magnesium isoglycyrrhizinate (MgIG) has anti-inflammatory, antioxidative, antiviral and anti-hepatotoxic effects. However, protective effects of MgIG against renal damage caused by arsenic trioxide (ATO) have not been reported. The present study aimed to clarify the protective function of MgIG on kidney damaged induced by ATO. Other than the control group and the group treated with MgIG alone, mice were injected intraperitoneally with ATO (5 mg/kg/day) for 7 days to establish a mouse model of kidney damage. On the 8th day, blood and kidney tissue were collected and the inflammatory factors and antioxidants levels in the kidney tissue and serum were measured. The expression of protein levels of caspase-3, Bcl-2, Bax, Toll-like receptor-4 (TLR4) and nuclear factor-κB (NF-κB) were determined via western blot analysis. In the renal tissue of mice, ATO exposure dramatically elevated markers of oxidative stress, apoptosis and inflammation. However, MgIG could also restore the activities of urea nitrogen and creatinine to normal levels, decrease the malondialdehyde level and reactive oxygen species formation and increase superoxide dismutase, catalase and glutathione activities. MgIG also ameliorated the morphological abnormalities generated by ATO, reduced inflammation and apoptosis and inhibited the TLR4/NF-κB signaling pathway. In conclusion, MgIG may mitigate ATO-induced kidney damage by decreasing apoptosis, oxidative stress and inflammation and its mechanism may be connected to the inhibition of TLR4/NF-κB signaling.Copyright: © Wei et al.