GESTATIONAL EXPOSURE TO THE AQUACONTAMINANT, NICKEL CHLORIDE IN FEMALE ZEBRA FISH, Danio rerio CULMINATES IN BEHAVIORAL AND NEUROCHEMICAL CHANGES IN PROGENY

Abstract

The prenatal period is essential period for neurodevelopment during which a range of exposures can exert long-term changes in the brain. The water-soluble salts of nickel, a heavy metal toxicant, are crucial contaminants in the environment including drinking water that can cause neurological damage. To assess the impact of gestational exposure to nickel chloride on the nervous system of the adult female fish. In the current study, Nickel chloride (3 μl of 1 M NiCl2) was injected intramuscularly in adult female Zebrafish for 30, 40 and 50 days. The time-dependent changes were assessed in the juvenile fish by performing histopathology, behavioral analysis, oxidant and antioxidant status and also the levels of neurotransmitters were examined. The results revealed that the Chronic stress due to NiCl2 was affected the Purkinje layer, increased anxiety and decreased the memory as evident from the tank diving and maze test in a duration-dependent manner. The oxidative stress as assessed by the level of lipid peroxidation showed increased in comparison to the control (p less than 0.001)). The response of tissue antioxidants as assessed by the activities of SOD,GST, catalase and the content of reduced glutathione were found to be affected at 50thday of induction. The activity of acetylcholine esterase and the level of nor adrenaline were significantly increased (p less than 0.001) on 50th day whereas the levels of serotonin and dopamine showed a significant reduction (p less than 0.001). Collectively the study suggests that the nickel chloride can alter the neuronal morphology, affect the behavior and neurotransmission, owing to possible developmental defects in the brain of the juvenile zebrafish.