The repairing effect of baicalein on lead induced damage to the gut-liver axis in tadpoles

Baicalein has pharmacological functions, such as antioxidant and anti-inflammatory properties, and has been shown to alleviate damage to organs caused by environmental pollutants. However, the mechanism by which baicalein reduces the toxic effects of metals needs further research. This study used Pelophylax nigromaculatus tadpoles as a model to explore the toxicological effects of lead (Pb) on the gut-liver axis, and the mechanism by which baicalein alleviates lead toxicity. Analysis of the gut microbiota showed that baicalein alleviated abnormal changes in the gut microbiota following Pb exposure, mainly by increasing the abundance of beneficial bacterial genera, including Cetobacterium, Clostridioides, and Monoglobus. Liver metabolomics showed that compared to a natural recovery, baicalein treatment significantly increased the content of metabolites such as uridine, 17α-hydroxypregnenolone, niacin, and cucurbitacin E, and significantly reduced the content of metabolites such as linoleic, gluconic acid, and tetrahydrocortisone. These differential metabolites could be enriched in pathways such as pyrimidine metabolism, nicotinic acid and nicotinamide metabolism, and steroid hormone biosynthesis, which were beneficial for the treatment of liver injury. There was a significant correlation between the gut microbiota and the main differential metabolites in the liver with the addition of baicalein. The improvement of these metabolic pathways by baicalein is beneficial for the repair of the liver and intestines. Therefore, baicalein can increase the abundance of beneficial gut microbiota, improve liver metabolism, and thus reduce the damage of Pb exposure to the gut-liver axis.