Exposure to prenatal PCBs shifts the timing of neurogenesis in the hypothalamus of developing rats. Issue 8 (15th August 2020)

• Record Type: Journal Article
• Authors: Hernandez Scudder, Morgan E.; Kunkel, Marcela Nicole; Gore, Andrea C.
• Is Part Of: Journal of experimental zoology. Volume 333:Issue 8(2020)
• Page Start: 550
• Page End: 560
• Publication Date: 2020-08-15
• Subjects: Aroclor 1221 -- endocrine‐disrupting chemical -- hypothalamus -- neurogenesis -- polychlorinated biphenyl -- preoptic area -- ventromedial nucleus; Zoology -- Periodicals; Zoology; Animal Population Groups -- physiology; Zoology; Electronic journals; Periodical; Periodicals; 590
• DOI: 10.1002/jez.2404
• Languages: English
• ISSNs: 2471-5646

Abstract

Abstract: The developing brain is highly sensitive to the hormonal milieu, with gonadal steroid hormones involved in neurogenesis, neural survival, and brain organization. Limited available evidence suggests that endocrine‐disrupting chemicals (EDCs) may perturb these developmental processes. In this study, we tested the hypothesis that prenatal exposure to a mixture of polychlorinated biphenyls (PCBs), Aroclor 1221, would disrupt the normal timing of neurogenesis in two hypothalamic regions: the ventromedial nucleus (VMN) and the preoptic area (POA). These regions were selected because of their important roles in the control of sociosexual behaviors that are perturbed in adulthood by prenatal EDC exposure. Pregnant Sprague–Dawley rats were exposed to PCBs from Embryonic Day 8 (E8) to E18, encompassing the period of neurogenesis of all hypothalamic neurons. To determine the birth dates of neurons, bromo‐2‐deoxy‐5‐uridine (BrdU) was administered to dams on E12, E14, or E16. On the day after birth, male and female pups were perfused, brains immunolabeled for BrdU, and numbers of cells counted. In the VMN, exposure to PCBs significantly advanced the timing of neurogenesis compared to vehicle‐treated pups, without changing the total number of BrdU+ cells. In the POA, PCBs did not change the timing of neurogenesis nor the total number of cells born. This is the first study to show that PCBs can shift the timing of neurogenesis in the hypothalamus, specifically in the VMN but not the POA. This result has implications for functions controlled by the VMN, especially sociosexual behaviors, as well as for sexual selection more generally. Abstract : The timing of neurogenesis is advanced by polychlorinated biphenyls (PCBs) in the ventromedial nucleus of the hypothalamus. Research Highlights: This study tested the hypothesis that prenatal exposure to polychlorinated biphenyls (PCBs), a family of endocrine‐disrupting chemicals, would alter the timing/pattern of neurogenesis in the developing hypothalamus. In the ventromedial nucleus (VMN), PCBs advanced the timing of neurogenesis, whereas there was no effect in the preoptic area. These results show VMN‐specific effects of PCBs on neural birth, a result that may relate to functions controlled by this brain region such as sociosexual behaviors.