Verapamil caused biochemical alteration, DNA damage, and expression of hepatic stress-related gene biomarkers in Nile tilapia, Oreochromis niloticus

Impacts of long-term exposure to sub-lethal verapamil (VRP) at 0.14, 0.28, and 0.57 mg L⁻¹ were examined for 60 days to find the effects on activities of metabolic catalysts as well as molecular reactions in Nile tilapia. Alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities in the liver increased significantly (p < 0.05) at high concentration of the drug while there was no significant difference in the activities of soluble phosphatases, corrosive phosphatase, and malate dehydrogenase in comparison with the control. Enzymes of gluconeogenesis, including fructose 1,6-bisphosphatase and glucose-6-phosphatase, were induced while RNA/DNA proportion in fish liver decreased significantly in the fish exposed to the VRP from the 15th day onwards. It caused DNA damage and upregulated expression of hsp70, cat, and sod in the liver, which were found to be correlated with concentration of the drug. Prolonged exposure to sub-lethal VRP could change activities of metabolic catalysts, causing harm to DNA and upregulating stress-related genes in the fish which suggested use of these biomarkers as early cautioning signs about the existence of the drug in aquatic ecosystems.