Effects of ovarian hyperstimulation on early embryo development: a study in a murine model
Controlled ovarian hyperstimulation (COH) is a protocol commonly applied in assisted reproduction techniques. It involves the pharmacological stimulation of the ovaries, in order to increase the number of oocytes recovered and fertilization probabilities. However, the concomitant increase in se...
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| Autores principales: | , , , , , , |
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| Formato: | Artículo revista |
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Universidad Nacional Córdoba. Facultad de Ciencias Médicas. Secretaria de Ciencia y Tecnología
2022
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| Acceso en línea: | https://revistas.unc.edu.ar/index.php/med/article/view/39077 |
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| Sumario: | Controlled ovarian hyperstimulation (COH) is a protocol commonly applied in assisted reproduction techniques. It involves the pharmacological stimulation of the ovaries, in order to increase the number of oocytes recovered and fertilization probabilities. However, the concomitant increase in sexual steroid levels are thought to negatively impact on embryo development. The aim of this study was to assess the possible impact of COH on ovulation, fertilization and preimplantation embryo development in a mouse model.
Albino Swiss (N:NIH) adult female mice were treated (COH group) with human menopausic gonadotropin and human chorionic gonadotropin (10 I.U/day each), and oocytes number and quality were recorded. A second COH group was mated with untreated males, and their uteri were removed (three days post coitus), in order to asses embryos/oocytes number and developmental stage (2-8 cells, early/late morula and compact/expanded blastocyst). The percentage of fertilization was calculated considering embryo and corpora lutea numbers. Females in natural estrous were used as the control group (C). Results were analyzed by T/Mann-Whitney test; in all cases p<0.05 was considered significant.
Ovulation rate was higher in COH vs. C (27.82±2.92 vs 10.15±0.71, n=17-13; p<0.05), but no differences were found in oocytes quality. The COH increased plasmatic progesterone (6.16±1.05ng/ml vs 0.78±0.29ng/ml; n=6-5; p<0.05), but not the estradiol levels. Although there were no significant differences in the percentage of fertilized oocytes, the COH group showed a delayed embryo development, evidenced by an increased in late morulas (78.83% vs 40.28%; n=11-9; p<0.05) and a decrease in blastocysts (15.25% vs 55.55%; n=11-9; p<0.05).
The supraphysiological levels of sexual hormones are a possible explanation for these effects, since sexual steroids could modify the epithelial-secreted cytokines profile, that are well known as embryo development modulators. We are currently performing studies in this regard. In summary, COH did not affect oocyte quality, but delayed early embryo development. These results are of potential clinical relevance.
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