Thallium exposure disturbs gut microbiota composition, metabolic function, and host gut energy metabolism in aged...

Gut microbiota regulates the development of environmental exposure-induced diseases. Although previous studies have reported the effect of thallium exposure on the gut microbiota of adult male mice, its effects on the aging gut microbiome, particularly in females, remain largely unexplored. Herein, we showed that thallium exposure for 4 weeks altered fecal microbial β diversity in aged female and male mice, whereas exposure for 2 weeks did not. Combined LEfSe and indicator analyses revealed that in aged female mice, thallium exposure for 2 weeks increased Oscillibacter abundance, while exposure for 4 weeks increased the abundance of Lactobacillus, Limosilactobacillus, Adlercreutzia, and Priestia. In aged male mice, thallium exposure for 2 weeks increased the abundance of Rikenella, Bifidobacterium, Proteus, Enterococcus, and Chryseobacterium, while exposure for 4 weeks increased the abundance of Incertae_Sedis, Bifidobacterium, Clostridium, Christensenellaceae_R-7_group, and UCG-009. PICRUSt2 functional prediction analysis showed that thallium exposure may also affect energy metabolism-related pathways in gut bacteria. Thallium exposure significantly decreased C16:1 abundance in the colon, but not in the cecum, of aged male mice. Protein levels revealed that thallium exposure enhanced glycolysis in the cecum and colon of aged mice. Collectively, our findings reveal significant thallium-induced perturbations in the gut ecosystem and host metabolism in both aged male and female cohorts, which may contribute to understanding thallium-induced health risks in the elderly.