EFFECT OF ALUMINUM CHLORIDE ON LOCOMOTION, ANXIETY, AND SOCIAL INTERACTION IN ADULT ZEBRAFISH

Resumo

INTRODUCTION: Aluminum (Al) is a widely distributed aquatic contaminant, released into the environment by human activities and natural processes (Fernández-Dávila et al., 2012). Studies have shown that Al exposure can cause neurotoxicity, as well as behavioral and molecular changes in aquatic organisms, affecting locomotion and cognition (Igbokwe et al., 2019). The zebrafish (Danio rerio) is a relevant animal model for investigating toxicological effects due to its rapid development, high fecundity, and conserved vertebrate biology, rendering them a powerful animal model for understanding the mechanisms of metal toxicity and for assessing the environmental impact of pollutants (Link amp; Collery, 2015). OBJECTIVE: The aim of this study is to evaluate the effect of aluminum chloride (AlCl3) on locomotion, anxiety, and social interaction in zebrafish. MATERIAL AND METHODS: Adult zebrafish were exposed to AlCl3 for 96 h at concentrations of 6.5 and 11 mg/L. The time spent in the upper and lower zones of the tank was used as an indicator of anxiety. In a natural environment, the normal behavior of zebrafish is to remain longer at the bottom, gradually exploring the upper part of the water column (Levin et al., 2007). In the social interaction, animals were individually placed in a central tank, flanked by an empty tank and another containing fish (stimulus side). Following a 1-min acclimation and 5-min recording, the duration spent in each section of the tank was quantified to assess preference between each side of the tank (non-stimulus or stimulus side). RESULTS: Exposure to 6.5 and 11 mg/L AlCl3 for 96 h did not promote significant changes in social interaction or distance moved compared to the control group. However, the analysis of anxiety-related behavior revealed a decrease (plt;0.05; n=10) in the time spent in the lower zone of the tank in the groups treated with AlCl3, compared to the control group. CONCLUSION: This effect may indicate anxiolytic-like behavior induced by exposure to AlCl3. Future experiments with extended AlCl₃ exposure will assess whether prolonged treatment further affects adult zebrafish behavior. Understanding the effects of aluminum is crucial to assessing its potential impact on aquatic ecosystems.