Effect of amoxicillin on cartilage and bone development in zebrafish and their molecular mechanisms

Amoxicillin, a beta-lactam antibiotic, is the preferred treatment for numerous common infections during pregnancy. However, it has been identified as an emerging environmental pollutant. Clinical and animal studies indicate that prenatal exposure to amoxicillin may pose fetal developmental toxicity risks. In view of the environmental exposure and clinical application status of amoxicillin, this study investigated the effects of amoxicillin exposure at different concentrations and embryonic stages on the overall development of zebrafish embryos, as well as the development of cartilage and bone, and their underlying mechanisms. Our findings revealed that embryonic exposure to amoxicillin inhibited the overall, cartilage, and bone development of zebrafish in a concentration (80-400 µmol/L) and stage (0-1.5 and 1.5-3.0 dpf) dependent manner. This inhibition was manifested as reduced head and body length, decreased head and eye area, shortened palatal and ceratohyal cartilage length, and diminished operculum bone area, with these effects persisting from the larval to the juvenile stage. Notably, early exposure to amoxicillin had a more pronounced impact on zebrafish embryonic cartilage development, attributed to the inhibition of the foxo3a signaling pathway. In contrast, late exposure to amoxicillin more significantly affected zebrafish embryonic bone development, associated with the inhibition of the jak2a/stat3 signaling pathway. This study has verified the toxicity of amoxicillin to cartilage and bone development and elucidated its potential mechanisms, providing a theoretical and experimental basis for evaluating the environmental exposure risk of amoxicillin and revealing its action patterns.