Liver damage and lipid metabolic dysregulation in adult zebrafish (Danio rerio) induced by spirotetramat

Spirotetramat, an insecticide derived from cycloketone and extensively utilized in agricultural production, has been reported to be toxic to an array of aquatic organisms. Previous studies have indicated that spirotetramat can cause toxicity such as impaired ovarian development and apoptosis in zebrafish, but its toxicological effects on lipid metabolism and liver health in zebrafish remain unclear. In this study, we explored the effects of spirotetramat exposure on zebrafish (Danio rerio) by examining key markers of lipid metabolism, alterations in gene expression related to this process, and histological characteristics of the liver. Spirotetramat significantly reduced the condition factor, triglycerides and low-density lipoprotein cholesterol levels at 2 mg/L. The expression of genes related to fatty acid synthesis (acacb), β-oxidation (acox1, pparda) and pro-inflammatory cytokines (tnf-α, il-1β) was downregulated. However, the expression of genes related to lipid transport and uptake (cd36, ppara) and output (apob) was upregulated. The activity of alanine aminotransferase was significantly inhibited. Histopathology results showed that spirotetramat exposure led to liver cell vacuolation and necrosis. In addition, molecular docking results of spirotetramat and lipid transport related protein (ACC, ApoB) in both zebrafish and human showed the binding energy of human proteins is lower than that for zebrafish, and that the number of hydrogen bonds formed was higher. It is speculated that spirotetramat may also pose a significant potential hazard to humans, potentially affecting human lipid metabolism and health. This study expunge shed light on the ecological toxicity of spirotetramat by showing how it disrupts lipid metabolism and causes tissue damage specifically in zebrafish liver, contributing to a deeper understanding of its harmful effects in aquatic environment.