Exposed to Mercury-Induced Oxidative Stress, Changes of Intestinal Microflora, and Association between them in Mice

Twelve Kunming mice were randomly divided into two groups (n = 6), and administered with distilled water containing 0 mg/L and 160 mg/L HgCl₂ respectively, with an experimental period of 3 days. Our results showed that mercury exposure significantly reduced weight gain in mice (P < 0.01). Through pathological observation of cecum tissues, significant pathological changes were observed in cecum tissues of mice exposed to mercury. Furthermore, mercury exposure not only significantly increased malondialdehyde (MDA) content in mice (P < 0.01) but also significantly decreased superoxide dismutase (SOD) activity (P < 0.01) and glutathione peroxidase (GSH) level in mice (P < 0.01). Furthermore, high-throughput sequencing analysis showed that at the genus level some microbial populations including Clostridiales, Lactobacillus, Treponema, Oscillospira, and Desulfovibrio were significantly increased whereas some microbial populations including S24-7, Acinetobacter, and Staphylococcus were significantly decreased. Moreover, correlation analysis indicated that microorganisms were not correlated with biomarkers of oxidative stress. In summary, mercury exposure reduced the growth performance of mice, resulting in gut microbiota alterations, and led to oxidative stress by increasing the concentration of malondialdehyde (MDA) and decreasing the concentration of superoxide dismutase (SOD) and glutathione peroxidase (GSH).