Analysis of cardiac developmental toxicity induced by m-cresol in early life of zebrafish and its mechanism

The compound m-Cresol, also referred to as 3-methylphenol,acts as a precursor in the creation of pesticides and plasticizers. This research has conducted a thorough evaluation of the toxic effects of m-cresol on the cardiac development of juvenile zebrafish, from 6 to 72 hpf. The study's results reveal that higher concentrations of m-Cresol, compared to lower ones, result in more severe heart abnormalities in zebrafish larvae. The pericardial edema becomes more pronounced, the atrial-ventricular distance gradually increases, and the absorption of nutrients is delayed. Furthermore, experimental studies have shown that m-cresol can cause excessive oxidative stress and apoptosis in juvenile zebrafish during their early developmental stages. Additionally, our transcriptomic analysis indicates that m-Cresol exposure may cause cardiac developmental toxicity in zebrafish larvae by affecting the expression levels of genes (Myosin VIIa:my17,Myosin XIV:my14, Alpha-cardiac actin:actc1a,and Non-muscular myosin heavy chain 9 A:myh9a) involved in the ion channel signaling pathway and cardiomyocyte development. These findings collectively demonstrate the developmental toxicity of m-Cresol to the hearts of larval zebrafish.