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|Title:||Development of Mouse Embryos in Vitro and in Vivo, Following Mechanical Division|
|Author(s):||Lawitts, Joel Arthur|
|Department / Program:||Animal Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Biology, Animal Physiology|
|Abstract:||Mouse embryos were divided in halves and in quarters to determine the capability of fractional embryos to develop into live fetuses. When embryos were divided in half at the 2-cell, 4-cell, 8-cell and morula stage, a higher percentage of blastocysts developed in vitro from half 8-cell embryos (93%), than from embryos divided at the other cell stages. When half embryos were transferred into pseudo-pregnant recipients, a higher percentage of live fetuses developed from half 4-cell embryos (13%) and half 8-cell embryos (8%), than from half 2-cell embryos (3%) or half morulae (1%). When half 4-cell and half 8-cell embryos were transferred into recipients at various times during the day, the highest percentage of live fetuses developed from half 4-cell embryos (37%) after transfers at 1100 hours, whereas the highest percentage of live fetuses developed from half 8-cell embryos (21%) after transfer at 1900 hours.
When mouse embryos were divided into quarters and then transferred into recipients, 39% of the quarter embryos implanted, yet no live fetuses resulted.
Mouse half embryos were incubated in Krebs-Ringer Bicarbonate (KRB), or a modified Krebs-Ringer Bicarbonate (mKRB) medium which prevented compaction. There was no major influence on the development in vitro of half embryos which were prevented from compacting for one cell cycle beyond the 8-cell stage, whereas fewer blastocysts resulted from embryos which were prevented from compacting for two cell cycles. There were also fewer cells in the inner cell mass from embryos which were prevented from compacting for two cell cycles. When these embryos were transferred into recipients at 0700 hours, there was no difference between the percentages of live fetuses which developed from half embryos incubated in KRB or mKRB. When embryos were transferred into recipients at 1100 hours, a lower percentage of live fetuses developed from half embryos incubated in mKRB, compared to half embryos incubated in KRB. Delaying compaction delayed the onset of blastocyst formation. Therefore, when embryos were transferred at 1100 hours, the stage of embryo development of mKRB embryos may not have matched the stage of pseudo-pregnancy of the recipients to the same degree as in the KRB embyros.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987.
|Date Available in IDEALS:||2014-12-16|