Olanzapine exposure disordered lipid metabolism, gut microbiota and behavior in zebrafish (Danio rerio).

Olanzapine (OLZ) is widely used in the treatment of schizophrenia, and its metabolic side effects have garnered significant attention in recent years. Despite this, the specific side effects of OLZ and the underlying mechanisms remain inadequately understood. To address this gap, zebrafish (Danio rerio) were exposed to OLZ at concentrations of 35.5, 177.5, and 355.5 μg/L. The results indicated that exposure to OLZ significantly increased body weight, total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG). Histological analysis revealed notable lipid accumulation in the liver. Furthermore, lipid synthesis genes, including sterol regulatory element binding protein (srebp), acetyl CoA carboxylase (acc), and fatty acid synthesis gene (fas), were up-regulated. In contrast, genes related to lipid decomposition, such as lipoprotein lipase (lpl), hormone-sensitive triglyceride lipase (hsl), and carnitine palmitoyltransferase 1b (cpt1b), were down-regulated. Subsequent analysis of zebrafish behavior showed reduced motor activity, sociability, and anxiety-like behavior in OLZ-exposed zebrafish, consistent with the results of neurotransmitter related gene expression. Following OLZ treatment, the expression of tryptophan hydroxylase (tph), tyrosine hydroxylase (th), dopamine transporter (dat), glutaminase (glsa), and glutamic acid decarboxylase 1b (gad1b) was upregulated. Additionally, the diversity of intestinal flora decreased after OLZ exposure, and the structure of the intestinal microbiota changed significantly compared to the control group. At the genus level, the abundance of Plesiomonas was upregulated, while the abundances of Bacillus and Cetobacterium were downregulated in the OLZ-exposed group. Furthermore, the results of the correlation analysis indicated that lipid metabolism and behavioral changes were closely associated with the microbiota. This study clarified the side effects of OLZ, and also provided a basis for the reasonable discharge concentration of OLZ in water and clinical drug use.