Chronic exposure to paclobutrazol causes hepatic steatosis in male rockfish Sebastiscus marmoratus and the mechanism involved

Paclobutrazol (PBZ) is a triazole-containing fungicide which is widely used in agriculture. Acute toxicity can follow its extensive use but it is generally weaker than traditional pesticides such as organochlorine and organophosphorus. However, its adverse effects on aquatic organisms need to be investigated. This study was conducted to investigate the effect of PBZ exposure on the hepatic lipid metabolism of Sebastiscus marmoratus. After PBZ exposure for 50 days, hepatic lipid droplets were enlarged and the hepatic total lipid, triglyceride, total cholesterol and free fatty acid content had increased in a dose dependent manner compared to the control. The mRNA expression of lipid metabolism associated genes such as peroxisome proliferator-activated receptors (PPARs), androgen receptor, acetyl-CoA carboxylase 1, fatty acid synthesis, fatty acid bing protein 4, liver X receptor α (LXRα) and stearoyl-CoA desaturase were up-regulated by PBZ exposure. These results indicated that triazole-containing fungicides might affect the metabolism and health of fish via the multi-signal pathways of nuclear receptors such as PPARs and LXR.

► Paclobutrazol exposure enlarged hepatic lipid droplets in male Sebastiscus marmoratus. ► The hepatic total lipid, triglyceride, total cholesterol and free fatty acid content increased significantly in 1000 ng/L group. ► The mRNA expression of genes related lipid metabolism was up-regulated by PBZ exposure. ► The disturbing of multi-signal pathways of nuclear receptors such as PPARs and LXR might be the main reason affecting the lipid metabolism.