Developmental Behavioral Alterations Following Lead (Pb) Exposure in the Zebrafish Model System

Lead (Pb) is a toxic heavy metal of concern that can be found in drinking water, dust, and soil. Environmental exposure to lead has been associated with neurologi-cal alterations in both adults and children. Numerous studies have suggested adverse health outcomes caused by the neurotoxic effects of lead on the central nervous system. This study used the zebrafish model to investi-gate the developmental toxicity effects of lead exposure from 1 to 120 hours post-fertilization (hpf) using 0, 10, 50, 100, 500, and 1,000 ppb of lead. The visual motor response test was used to assess changes in behavior and locomotion. Phasic data was collected and analyzed using a repeated measures ANOVA. Phasic behavior data showed hyperactivity through increased velocity and distance moved in all of the dark phases for the 10 ppb treatment group ( p < 0.05). Larvae in the 50 ppb treatment group showed hyperactivity in the second light phase through increased velocity, time spent moving, and distance traveled ( p < 0.05). Hypoactivity, depicted through decreased velocity, distance moved, and time spent moving occurred in the 100 ppb treatment group in the first light phase ( p < 0.05). Larvae in the 500 ppb treatment group only exhibited a decreased time spent moving in the first two dark phases and first light phase ( p < 0.05). The 1,000 ppb treatment group spent less time moving only in the first dark phase ( p < 0.05). These findings indicate zebrafish larvae that were exposed to lead early in development display various changes in behavior and locomotive activity dependent on lead exposure concentration.