OR06-03 Intergenerational Exposure To Endocrine-disrupting Chemicals (Edcs) Affects Dopamine-mediated Behaviors In A Sex-Specific Manner In Rats

Abstract

Abstract Disclosure: E.N. Hilz: None. C. Schnurer: None. S. Bhamidipati: None. L. Thompson: None. E. Morales-Ledesma: None. A.C. Gore: None. Polychlorinated biphenyls (PCBs) are a weakly estrogenic class of ubiquitous environmental EDCs that affect a range of sex-specific neuroendocrine and reproductive outcomes. Furthermore, these effects can extend intergenerationally via epigenetic changes carried down the germline. In humans, PCBs are associated with sexually dimorphic and hormone sensitive neurobehavioral disorders including attention deficit hyperactivity disorder (ADHD) and mood disorders such as depression; however, little preclinical work has modeled these cognitive changes in rats and none has determined if they extend intergenerationally via endocrine-mediated changes to the brain dopamine system. In the current work, three generations of male and female Sprague-Dawley rats were exposed to the PCB mixture Aroclor 1221 (A1221) at different life stages: as adults; through perinatal exposure via mother's diet; or preconceptionally, as the germ cells within the exposed fetus. Adults of each generation underwent a battery of behavioral tasks to assess attentional phenotype, cognitive flexibility, and affect as measured by attentional set-shifting, conditioned orienting, and sucrose preference tests. These outcomes were correlated with both serum estradiol concentrations and dopamine cell quantity in the midbrain. Results revealed that A1221 treatment had sex- and generation-specific effects: in adult-exposed females, decreased conditioned orienting suggested a hyporesponsive attentional phenotype; in males, preconceptional exposure reduced cognitive flexibility via impaired attentional set-shifting. All rats showed a strong preference for sucrose solution; however, A1221 treatment decreased the total amount of sucrose solution consumed (indicating anhedonia) regardless of sex or timing of exposure. Dopamine cell numbers were inversely affected by A1221 between the sexes: decreased in females and increased in males, which correlates well with the cognitive changes observed. Relationships among estradiol concentration, cognitive changes, and dopamine cell quantity will be ascertained using a multilevel model that accounts for endocrine-mediated disruptions at the brain, body, and behavioral levels. These data show that the PCB mixture A1221 impairs different aspects of cognitive behavior between the sexes depending on timing of exposure, while having a broader effect of increased anhedonia, in a manner potentially mediated by hypo- or hyper-availability of midbrain dopamine and serum estradiol. Supported by RO1 ES029464. Presentation: Thursday, June 15, 2023