Moderating effect of salidroside on intestinal microbiota in mice exposed to PM2.5

Background Salidroside (SAL) has a protective effect on multiple organ systems. Exposure to fine particulate matter (PM2.5) in the atmosphere may lead to disruptions in gut microbiota and impact intestinal health. The regulatory effect of SAL on the gut microbiota of mice exposed to PM2.5 requires further investigation. Objective To evaluate gut microbiota disruption in mice after being exposed to PM2.5 and the potential effect of SAL. Methods Forty male C57BL/6 mice, aged 6 to 8 weeks, were randomly divided into four groups: a control group, an SAL group, a PM2.5 group, and an SAL+PM2.5 group, each containing 10 mice. In the SAL group and the SAL+PM2.5 group, the mice were administered SAL (60 mg·kg−1) by gavage, while in the control group and the PM2.5 group, sterile saline (10 mL·kg−1) was administered by gavage. In the PM2.5 group and the SAL+PM2.5 group, PM2.5 suspension (8 mg·kg−1) was intratracheally instilled, and in the control group and SAL group, sterile saline (1.5 mL·kg−1) was intratracheally administered. Each experiment cycle spanned 2 d, with a total of 10 cycles conducted over 20 d. Histopathological changes in the ileum tissue of the mice were observed after HE staining. Colon contents were collected for gut microbiota sequencing and short-chain fatty acids (SCFAs) measurements. Results The PM2.5 group showed infiltration of inflammatory cells in the ileum tissue, while the SAL+PM2.5 group exhibited only a small amount of inflammatory cell infiltration. Compared to the control group, the PM2.5 group showed decreased Shannon index (P