190 The combination of oestrus synchronisation and superovulation treatments negatively impact embryo viability through the downregulation of Wnt/β-catenin signalling genes in the porcine endometrium
H. Gonzalez-Ramiro A , I. Parrilla A , J. Cambra A , A. Gonzalez-Plaza A , M. Gil A , C. Cuello A , E. Martinez A , H. Rodriguez-Martinez B and C. Martinez B CA Department of Medicine and Animal Surgery, Faculty of Veterinary Medicine, University of Murcia, Murcia, Spain
B Department of Biomedical & Clinical Sciences, BKH/Obstetrics & Gynaecology, Linköping University, Linkping, Sweden
C Department of Animal Reproduction, National Institute for Agriculture and Food Research and Technology, Madrid, Spain
Reproduction, Fertility and Development 35(2) 223-223 https://doi.org/10.1071/RDv35n2Ab190
Published: 5 December 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
The combined use of oestrus synchronisation and superovulation treatments introduce endocrine modifications, the effects of which are yet to be disclosed. Here, reproductive parameters and gene expression changes in ovaries and endometrium were explored on Day 6 after artificial insemination (AI), when the synthetic progestin Altrenogest (ALT) was combined with gonadotrophins. Sows were administered ALT for 7 days beginning on the day of weaning and were superovulated with equine chorionic gonadotrophin (eCG) 24 h after the last administration of ALT, and human chorionic gonadotrophin (hCG) at the onset of oestrus (SS-7 group; n = 5). Superovulated sows with eCG 24 h after weaning and hCG at the beginning of oestrus (SC group; n = 5) and sows with postweaning natural oestrus (NC group; n = 5) constituted the control groups. Ovary examination and embryo and tissue collection were performed in all sows via laparotomy on Day 6 post-AI. RNA-Seq was used to analyse differentially expressed genes (DEGs) among groups. Reproductive parameters were compared with ANOVA and Bonferroni post hoc tests. Analyses of DEGs were performed with ANOVA (fold change > 2 or < −2 with P-value < 0.05). Hormonal treatments almost doubled (P < 0.03) the number of corpora lutea (39.8 ± 10.2 and 38.3 ± 11.1 in SS7 and SC sows, respectively) compared with the NC group (23.1 ± 3.8). In contrast, embryo viability was significantly decreased (P < 0.003) in response to SS-7 treatment (60.3 ± 15.2%) compared with SC and NC groups (93.8 ± 7.6% and 91.8 ± 6.9%, respectively). RNA-Seq analyses revealed 675 and 1,583 DEGs in the SS-7 group compared with both control groups in endometrial and ovarian samples, respectively. Interestingly, many genes with key roles in the Wnt/β-catenin signalling pathway were differentially expressed in SS-7 sows relative to SC and NC groups (e.g. CTNNB1, MYC, GLI3, SCYL2, CCNY, DAAM1, PPM1N, RBPJ, USP8). Wnt/β-catenin signalling is crucial for embryo development up to the blastocyst stage and for the acquisition of blastocyst competency for implantation. One of the key findings in this study was the downregulation of the β-catenin (CTNNB1) gene expression in the SS-7 endometrium, suggesting an influence of this treatment on embryo-uterine dialogue that may trigger a cascade of events leading to embryo maldevelopment. The data explain the proliferative defects in SS-7 embryos and suggest a novel mechanism for porcine embryo-maternal crosstalk.
This research was supported by MCIN/AEI/ERDF (RTI2018-093525-B-I00), Seneca (19892/GERM/15) and FORMAS (2019-00288).
