Differential influence of molybdenum disulfide at the nanometer and micron scales in the intestinal metabolome and microbiome of mice

The molybdenum disulfide nanomaterial (nano-MoS2) is receiving increasing amounts of attention due to its special physicochemical characteristics. However, little is known about the influence of the different sizes of MoS2 on the intestinal metabolome and microbiome. In this study, C57BL/6 mice were exposed to nano-MoS2 and MoS2 micromaterials (micro-MoS2) via food premixed with 15 and 150 mg MoS2 per kg food for 90 days. The results showed that nano-MoS2 and micro-MoS2 exposure induced Mo accumulation in mouse organs, especially in the small intestine (SI) and large intestine (LI). Nano-MoS2 had a higher bioavailability and caused greater intestinal inflammation than micro-MoS2. Metabolome analyses showed that both types of MoS2 exposure changed the metabolic profiles of the intestine and intestinal microbiota. Ten and eight significantly altered microbial-host cometabolites were found in the SI and LI, respectively, and these were primarily involved in amino acid and carbohydrate metabolism. Additionally, both types of MoS2 exposure obviously changed the intestinal microbiota, especially in the LI. Correlation analysis suggests that micro-MoS2 could alter the intestinal metabolic profiles by changing the microbial community, but nano-MoS2 could cause similar effects by changing the microbial community and direct intestine toxicity. This study provides insights into the toxicity and health risks of nano-MoS2 and micro-MoS2 introduced by oral exposure.