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De La Torre KM, Lee Y, Safar A, Laws MJ, Meling DD, Thompson LM, Streifer M, Weis KE, Raetzman LT, Gore AC, Flaws JA. Prenatal and postnatal exposure to polychlorinated biphenyls alter follicle numbers, gene expression, and a proliferation marker in the rat ovary. Reprod Toxicol 2023; 120:108427. [PMID: 37400041 PMCID: PMC10528725 DOI: 10.1016/j.reprotox.2023.108427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/15/2023] [Accepted: 06/20/2023] [Indexed: 07/05/2023]
Abstract
Polychlorinated biphenyls (PCBs) were used in industrial applications until they were banned in the 1970s, but they still persist in the environment. Little is known about the long-term effects of exposure to PCB mixtures on the rat ovary during critical developmental periods. Thus, this study tested whether prenatal and postnatal exposures to PCBs affect follicle numbers and gene expression in the ovaries of F1 offspring. Sprague-Dawley rats were treated with vehicle or Aroclor 1221 (A1221) at 1 mg/kg/day during embryonic days 8-18 and/or postnatal days (PND) 1-21. Ovaries from F1 rats were collected for assessment of follicle numbers and differential expression of estrogen receptor 1 (Esr1), estrogen receptor 2 (Esr2), androgen receptor (Ar), progesterone receptor (Pgr), and Ki-67 (Ki67) at PNDs 8, 32, and 60. Sera were collected for measurement of estradiol concentrations. Prenatal exposure to A1221 significantly decreased the number of primordial follicles and the total number of follicles at PND 32 compared to control. Postnatal PCB exposure borderline increased Ki67 gene expression and significantly increased Ki67 protein levels (PND 60) compared to control. Combined prenatal and postnatal PCB exposure borderline decreased Ar expression (PND 8) compared to control. However, PCB exposure did not significantly affect the expression of Pgr, Esr1, and Esr2 or serum estradiol concentrations compared to control at any time point. In conclusion, these data suggest that PCB exposure affects follicle numbers and levels of the proliferation marker Ki67, but it does not affect expression of some sex steroid hormone receptors in the rat ovary.
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Affiliation(s)
- Kathy M De La Torre
- Department of Comparative Biosciences, University of Illinois, Urbana, IL, USA
| | - Yuna Lee
- Department of Comparative Biosciences, University of Illinois, Urbana, IL, USA
| | - Adira Safar
- Department of Comparative Biosciences, University of Illinois, Urbana, IL, USA
| | - Mary J Laws
- Department of Comparative Biosciences, University of Illinois, Urbana, IL, USA
| | - Daryl D Meling
- Department of Comparative Biosciences, University of Illinois, Urbana, IL, USA
| | - Lindsay M Thompson
- Division of Pharmacology and Toxicology, University of Texas, Austin, TX, USA
| | - Madeline Streifer
- Division of Pharmacology and Toxicology, University of Texas, Austin, TX, USA
| | - Karen E Weis
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL, USA
| | - Lori T Raetzman
- Department of Molecular and Integrative Physiology, University of Illinois, Urbana, IL, USA
| | - Andrea C Gore
- Division of Pharmacology and Toxicology, University of Texas, Austin, TX, USA
| | - Jodi A Flaws
- Department of Comparative Biosciences, University of Illinois, Urbana, IL, USA.
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Weis KE, Thompson LM, Streifer M, Guardado I, Flaws JA, Gore AC, Raetzman LT. Pre- and Postnatal Developmental Exposure to the Polychlorinated Biphenyl Mixture Aroclor 1221 Alters Female Rat Pituitary Gonadotropins and Estrogen Receptor Alpha Levels. Reprod Toxicol 2023; 118:108388. [PMID: 37127253 DOI: 10.1016/j.reprotox.2023.108388] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/11/2023] [Accepted: 04/28/2023] [Indexed: 05/03/2023]
Abstract
Polychlorinated-biphenyls (PCBs) are industrial compounds, which were widely used in manufacturing of electrical parts and transformers. Despite being banned in 1979 due to human health concerns, they persist in the environment. In humans and experimental model systems, PCBs elicit toxicity in part by acting as endocrine-disrupting chemicals (EDCs). Aroclor 1221 (A1221) is a weakly estrogenic PCB mixture known to alter reproductive function in rodents. EDCs can impact hormone signaling at any level of the hypothalamic-pituitary-gonadal (HPG) axis, and we investigated the effects of A1221 exposure during the prenatal and postnatal developmental periods on pituitary hormone and steroid receptor expression in female rats. Examining offspring at 3 ages, postnatal day 8 (P8), P32 and P60, we found that prenatal exposure to A1221 increased P8 neonate pituitary luteinizing hormone beta (Lhb) mRNA and LHβ gonadotrope cell number while decreasing LH serum hormone concentration. No changes in pituitary hormone or hormone receptor gene expression were observed peri-puberty at P32. In reproductively mature rats at P60, we found pituitary follicle stimulating hormone beta (Fshb) mRNA levels increased by prenatal A1221 exposure with no corresponding alterations in FSH hormone or FSHβ expressing cell number. Estrogen receptor alpha (ERα) mRNA and protein levels were also increased at P60, but only following postnatal A1221 dosing. Together, these data illustrate that exposure to the PCB A1221, during critical developmental windows, alters pituitary gonadotropin hormone subunits and ERα levels in offspring at different phases of maturation, potentially impacting reproductive function in concert with other components of the HPG axis.
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Affiliation(s)
- Karen E Weis
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign
| | | | - Madeline Streifer
- Division of Pharmacology and Toxicology, University of Texas at Austin
| | - Isabella Guardado
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County
| | - Jodi A Flaws
- Department of Comparative Biosciences, University of Illinois College of Veterinary Medicine
| | - Andrea C Gore
- Division of Pharmacology and Toxicology, University of Texas at Austin
| | - Lori T Raetzman
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign.
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Streifer M, Gore AC. Epigenetics, estrogenic endocrine-disrupting chemicals (EDCs), and the brain. Endocrine-Disrupting Chemicals 2021; 92:73-99. [DOI: 10.1016/bs.apha.2021.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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