This study aimed to further investigate the toxic mechanism of chiral
polychlorinated biphenyl (PCB) 91 in adult zebrafish ( Danio rerio) exposed to racemic (rac-), (+)-, or (-)-PCB91 for 63 days. The enantioselective mortalities of adult zebrafish exposed to rac-/(+)-/(-)-
PCB91 were 95.86, 50.08, and 81.50%, respectively. Tubular
necrosis and cellular
hypertrophy occurred in the kidneys of (-)-PCB91-treated groups, whereas
demyelination and immune cell infiltration occurred in brains of the rac-, (+)-, and (-)-PCB91-treated groups. Additionally, exposure to chiral
PCB91 enantioselectively induced neurotoxicity, apoptosis, and
inflammation in brain tissues owing to perturbations of gene expression,
protein content and
sphingolipid levels. The high mortality after rac-/(+)-
PCB91 exposure might be due to toxic effects on brain tissue, while the high mortality after (-)-PCB91 exposure might be due to toxic effects on kidney as well as brain tissues. Thus, our findings offer an important reference for elucidating the enantioselective toxicological mechanism of chiral
PCBs in aquatic organisms.