Abstract
Radioactive compounds, including silicon dioxide (31SiO2), may enter the environment and affect biological systems, yet their impact on the gut microbiota remains poorly studied. This study aimed to evaluate the effects of radioactive 31SiO2, compared to non-radioactive SiO2 and gamma irradiation, on the composition and functionality of the gut microbiota in laboratory Wistar rats (n = 28). Gut microbiota analysis of the large intestine, small intestine, and Peyer’s patches was conducted at 90 min and 72 h post-exposure using 16S rRNA sequencing. Alpha-diversity results showed increased species richness in Peyer’s patches at 90 min after exposure to radioactive 31SiO2, with elevated Bacilli and Gammaproteobacteria, a trend persisting at 72 h. In the small intestine, radioactive 31SiO2 increased Bacilli and Clostridia at 3 days, while Gammaproteobacteria considerably decreased; by 72 h, Bacilli and Clostridia maintained growth, with Gammaproteobacteria recovering. These findings demonstrate that radioactive 31SiO2 dynamically alters gut microbiota composition and diversity, highlighting its unique influence on microbial communities.