Epigenetic changes and phenotypic impact through successive applications of a program of embryo vitrification
[EN] The assisted reproductive technologies (ART) are increasingly used. However, in the last years, several studies have demonstrated the harmful effects associated with ART. There are more and more epigenetic studies corroborate that this differences between ART individuals and naturally conceived...
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| Format: | master thesis |
| Publication Date: | 2020 |
| Country: | España |
| Institution: | Universitat Politècnica de València (UPV) |
| Repository: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Language: | English |
| OAI Identifier: | oai:riunet.upv.es:10251/148968 |
| Online Access: | https://riunet.upv.es/handle/10251/148968 |
| Access Level: | Open access |
| Keyword: | Vitrificación Embrión Plasticidad Epigenética Crecimiento Vitrification Embryo Plasticity Epigenetic Growth PRODUCCION ANIMAL Máster Universitario en Mejora Genética Animal y Biotecnología de la Reproducción-Màster Universitari en Millora Genètica Animal i Biotecnologia de la Reproducció |
| Summary: | [EN] The assisted reproductive technologies (ART) are increasingly used. However, in the last years, several studies have demonstrated the harmful effects associated with ART. There are more and more epigenetic studies corroborate that this differences between ART individuals and naturally conceived individuals produce marks in the genome. The adaptations of the embryo to the suboptimal conditions and stress on account of the vitrification during the development programming have consequences even at neonatal period or adulthood. The presented study aimed to evaluate the impact through successive applications of an embryo vitrification procedure on growth pattern and DNA methylation in liver tissue at adulthood. Initially, 2 experimental populations were developed: one from vitrified embryos transferred to the surrogate mothers (VT) and other from naturally conceived animals (NC). In both experimental groups, females were artificially inseminated (AI) with semen of unrelated males from the same strain. In the VT group, 3 days after AI, the embryos were recovered, vitrified and then transferred to surrogate mothers by laparoscopy. Meanwhile, NC offspring were generated letting the females give birth after AI. When the animals of first generation (F0) were in reproductive age, they were used to establish the second generation (F1) with the same procedure. The same procedure was utilized to generate third generation (F2) with F1 animals. At F0, F1 and F2, after delivery, offspring were weighed at birth, 4, 9, and 20 weeks. Growth curves were also estimated by nonlinear regression using the Gompertz equation, well suited for rabbits. At 56 weeks of age, animals of F0 and F1 were euthanized and 10 liver samples for each generation (5 VT and 5 NC) were taken. Over this samples, epigenetic study was performed. Our data showed that in F0 and F2 VT offspring exhibited differences significantly in the growth pattern, but, in F1, the offspring present a similar growth pattern. DNA methylation analysis reveals differences in methylation pattern between VT and NC animals in both generations. The comparative epigenomic analysis revealed 406 differentially methylated regions (DMRs) in F0, of which 61.1% were hypomethylated in VTF0 samples compared to the NCF0 ones; and 570 DMRs in F1, of which 56.0% were hypomethylated in VTF1 samples compared to the NCF1 ones. In conclusion, embryonic manipulation during the vitrification process is linked with embryo phenotypic adaptation detected at adulthood. The phenotypic variation during the vitrification process may be associated with alterations in the genome methylation patterns in the liver tissue. Further research is needed to validate the significance of this finding. |
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