In our working hypothesis we did not take into consideration the possibility that NSN oocytes would develop to the 4-cell stage. As we reported before, intermediate forms of oocyte chromatin organization between the NSN and SN patterns exist. Whereas SN oocytes are easy to recognize (a complete ring of chromatin surrounding the nucleolus and a […]
The NSN and SN oocytes that we isolated from the antral compartment after hCG injection and ovulation may either have lacked some of the factors involved in the reorganization of the chromatin or have had some factors that inhibited or altered this reorganization. Two-cell embryos derived from SN and NSN oocytes isolated after hCG injection […]
In eCG Alone, More SN Oocytes Develop to the 4-Cell Stage Than Do NSN Oocytes After fertilization, SN oocytes were more prone to early embryonic development and to reach the 1-cell stage than their NSN counterparts in both eCG-only and the eCG+hCG experiments (Tables 1, 2, and 3).
Oocytes isolated 48 h after eCG injection were cultured for 15 h in order to allow them to reach the Mil stage (a longer time in culture did not significantly improve the percentage of oocytes maturing to Mil; data not shown); oocytes isolated 15 h after hCG injection instead took 24 h to reach the […]
This first set of data supports our working hypothesis: 1) whatever the treatment, the meiotic competence of SN oocytes was superior to that of NSN oocytes and was comparable to, and usually superior to, that of control oocytes (control oocytes represented a mixture of SN + NSN oocytes: the coculture with NSN oocytes might have […]
Both NSN and SN Oocytes Are Capable of Resuming Meiosis The regulation of meiotic maturation of the mammalian oocyte, both in vivo and in vitro, is not fully understood. Under our experimental conditions, the three groups of antral oocytes analyzed (control, SN, and NSN oocytes) attained the MI stage in vitro in very high numbers […]
In this cytological study, we looked for a correlation between the chromatin organization of the antral oocyte nucleus and its meiotic competence and embryonic development potential. Our working hypothesis is that, after a surge of a follicle-stimulating hormone (eCG), those antral oocytes that exhibit a highly condensed nuclear and nucleolar chromatin (SN oocytes) are ready […]