Chlorpyrifos Causes Histopathological Changes and Modulates Vitellogenin Levels in Zebrafish (Danio Rerio)

Abstract

Chlorpyrifos is the most widely used insecticide worldwide for domestic and agricultural purposes. It is also an endocrine-disrupting chemical that affects non-target organisms even at low concentrations. The present study aimed to investigate sublethal concentration of chlorpyrifos in male zebrafish, focusing on its endocrine-disrupting effects on vitellogenin levels and tissue-level impact, as determined by histopathology. In our study, zebrafish were exposed to chlorpyrifos at concentrations of 10 and 100 µg/L for 24 h and 7 days, and compared to a control group. The results of vitellogenin levels revealed that exposure to sublethal concentrations caused significant increases (p < 0.05). Histopathological changes, including hyperplasia and epithelial detachment, were observed in the gill tissue. Hyperemia and hydropic degeneration were observed in liver tissue, hyperemia in brain tissue, and cavum glomeruli expansion and tubular degeneration in kidney tissue. In testicular tissue, degeneration and a decrease in sperm cells were detected at a 100 µg/L chlorpyrifos concentration after 24 h and 7 days. The results of this study indicate that chlorpyrifos can impact aquatic life and health even at extremely low concentrations.