Comparative study of the effects of carbamazepine in vivo and ex vivo on the regulation of brain genes in Astyanax lacustris (Characiformes: Characidae)

Abstract

Population growth has been harming aquatic ecosystems, and several studies have focused on the effects of environmental contaminants, especially emerging contaminants of concern (CECs), which can cause short and long-term environmental damage to organisms. Among these CECs, carbamazepine (CBZ) stands out, a neuropharmaceutical used in the treatment of neuropathologies, which when in the environment, can indirectly affect the neuroendocrine system in teleosts. The aim of this project is to investigate the effects of CBZ on the regulation of brain genes that control reproduction in A. lacustris. This study will use two approaches: in vivo and ex vivo. In vivo: sexually mature male A. lacustris (n = 96) will be exposed for 7 days (n = 8 per aquarium, in triplicate) to environmentally relevant concentrations of CBZ in the following experimental groups: 1) control with vehicle (DMSO - dimethyl sulfoxide); 2) 250 ng L-1 of CBZ; 3) 500 ng L-1 of CBZ; 4) 1250 ng L-1 of CBZ. Ex vivo: direct exposure of the brains will be performed to evaluate the effect of CBZ in a range of increasing concentrations (0; 100, 1000 ng/L). Considering the neurological function of CBZ, biomarkers of gene expression that participate in both the stimulation and inhibition of reproduction, located in the brain, the organ that is at the beginning of the neuroendocrine control axis of reproduction, will be evaluated. Initially, the transcriptome of this organ will be performed to access the specific sequences of the genes of interest. These biomarkers will provide insights into the action of CBZ on gene expression regulation, enabling understanding of its effects on the brain and reproduction control of a non-target species.