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Early Impacts of in Utero Exposure to Ethinylestradiol or Genistein on Rat Perinatal Testis Development and Germ Cells Transcriptome

Lecante, Laetitia L., Gaye, Bintou, Tremblay, Amélie et Delbès, Géraldine . Early Impacts of in Utero Exposure to Ethinylestradiol or Genistein on Rat Perinatal Testis Development and Germ Cells Transcriptome In: Society of Reproduction-53rd Annual Meeting, 8-12 July 2020, virtuel.

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Résumé

Although the male fertility decline is believed to be partly driven by environmental exposures during critical developmental periods, the underlying molecular mechanisms are still poorly understood. Spermatogenesis is based on the self-renewing reservoir of spermatogonial stem cells (SSCs) established during perinatal life from the differentiation of fetal male germ cells named gonocytes. Studies have shown that fetal exposure to high doses of xenoestrogens can affect testis development, global gene expression and decrease gonocytes number, which could lead to long-term impairment of male fertility. But only very few studies evaluated repercussions of environmentally relevant doses of xenoestrogens and their specific impact on gonocytes transcriptome. We hypothesized that fetal exposure to xenoestrogens could have short term effects on gonocytes transcriptome and affect their differentiation. Germ cell-specific GFP (GCS-EGFP rats) transgenic Sprague Dawley dams were gavaged from gestational days (GD) 13 to 19 with 2 μg/kg/d of ethinylestradiol (EE2), 10 mg/kg/d of genistein (GE) or vehicle. Sampling was done at GD20 or on post-natal day (PND) 5 (n=4 litter/group/age). Pregnant dams exposed to EE2 gained 10% less weight during treatment compared to controls but none of the treatments affected the number of pups/litter, sex ratio, anogenital distance or progeny body and gonadal weights. Serum was collected from each male and pooled per litter to measure testosterone levels. Only GE significantly decreased circulating testosterone at GD20. AT each stage, 2 testes per litter were collected and fixed for histological analyses. Others from that litter were pooled and dissociated to sort gonocytes. Using GCS-EGFP rats allowed to obtain purified gonocytes by fluorescence-activated cell sorting, with more than 90% purity. RNA were extracted from GFP-positive sorted cells and probed on Affymetrix Rat Gene 2.0 ST Arrays. Testicular histology was not altered and further quantification indicated that neither germ nor Sertoli cells densities were altered by treatments at both stages. Nevertheless, analysis of differentially expressed genes (DEG) (p<0.05; fold change 1.5) in GFP-positive cells showed that significant changes in the expression of 116 and 100 transcripts were induced by EE2 and GE respectively at GD20, and 276 and 160 transcripts respectively at PND5. Surprisingly, only about 1% were common between the two stages in each treatment. As well, in each stage, only about 6% were common between treatments suggesting different modes of action. Nevertheless, functional analysis of coding DEG revealed an overrepresentation of olfactory receptor activity in all groups. In parallel, many non-coding RNAs were affected by both treatments, representing more than 40% of DEG at GD20 and around 30% at PND5. Further analyses are ongoing to compare the effects on germ cells transcriptome to the somatic cells ones, using the GFP-negative sorted cells. Our data suggest that despite no immediate toxic effects, fetal exposure to xenoestrogens can modify germ cells transcriptome. The increased number of DEG from GD20 to PND5 while exposure has ended may suggest an imprint of early exposure that may impact their differentiation potentially altering future SSCs. This project is funded by Natural Sciences and Engineering Research Council of Canada.

Type de document: Document issu d'une conférence ou d'un atelier
Informations complémentaires: Affiche scientifique numéro du résumé 1964 pages 61 et 62 du document
Mots-clés libres: -
Centre: Centre INRS-Institut Armand Frappier
Date de dépôt: 14 juill. 2021 16:02
Dernière modification: 14 juill. 2021 16:02
URI: https://espace.inrs.ca/id/eprint/11815

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