Reproductive technologies could be markedly improved by the development of methods to evaluate oocyte and/or embryo quality in a non-invasive, quantitative manner. Previous work from this lab has shown that human embryos secrete factors that inhibit progesterone and estradiol production by granulosa cells. To determine if the presence of the progesterone-inhibitory factor (PIF) and estradiol-regulatory factor in human embryo-conditioned (HEC) media correlates with the health and developmental capacity of the embryos, an interspecies bioassay was established. Oocyte-cumulus complexes were isolated from superovulated mouse ovaries, the oocytes were microsurgically removed and the oocytectomized complexes were cultured in (HEC) media for 48 hours in the presence of FSH and testosterone. Steroid accumulation in the media was determined by radioimmunoassay. Despite the potential limitations of very small volumes of HEC media to evaluate, and the need to freeze this media at the source, the bioassay was able to detect PIF activity in HEC media, but no success was achieved measuring estradiol-regulatory factor. Most embryos produced PIF activity, but the degree of inhibition did not correlate with the ability of the oocytes to be fertilized nor with embryo morphology or their ability to cleave and develop after transfer. The role of the oocyte-specific protein, growth differentiation factor-9 (GDF-9), in cumulus expansion and steroidogenesis was also investigated to determine its potential as a marker for oocyte and embryo quality. Results with (HEC) media demonstrated that the secretion of PIF by human embryos could be measured by this bioassay and that human PIF could inhibit murine granulosa cell steroidogenesis; however, PIF activity did not correlate with human embryo quality or developmental competence. GDF-9 was shown to enable cumulus expansion and inhibit progesterone and stimulate estradiol production by murine cumulus granulosa cells.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/8587 |
| Date | January 2000 |
| Creators | Dhawan, Anil. |
| Contributors | Vanderhyden, Barbara, |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Detected Language | English |
| Type | Thesis |
| Format | 99 p. |
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