Compartment-specific rats' gut microbiome responses to internal irradiation by radioactive silicon dioxide (31SiO2) microparticles

Radioactive compounds, including silicon dioxide (SiO₂), may enter the environment and affect biological systems, yet their impact on the gut microbiome remains poorly studied. This study aimed to evaluate the effects of radioactive SiO₂, compared to non-radioactive SiO₂ and gamma irradiation, on the composition and functionality of the gut microbiome in laboratory Wistar rats (n=28). Microbiota analysis of the large intestine, small intestine, and Peyer’s patches was conducted at 90 minutes and 72 hours post-exposure using 16S rRNA sequencing. Alpha-diversity results showed an increase in unique species in Peyer’s patches at 90 minutes after exposure to radioactive 31SiO₂, with elevated Bacilli and Gammaproteobacteria, a trend persisting at 72 hours. In the small intestine, radioactive 31SiO₂ increased Bacilli and Clostridia at 3 hours, while Gammaproteobacteria considerably decreased; by 72 hours, Bacilli and Clostridia maintained growth, with Gammaproteobacteria recovering.