Confirmed dioestrus in pseudopregnant mice using vaginal exfoliative cytology improves embryo transfer implantation rate.
Embryo transfer is a commonly performed surgical technique. In mice, protocols typically specify pairing recipient females with vasectomized males to induce a receptive uterine environment for embryo implantation. However, this induced receptive state is not always maintained until implantation occurs. The use of a well-characterized correlation between oestrous state and exfoliative vaginal cytology was therefore evaluated to assess uterine receptivity immediately before embryo transfer. Eight- to 12-week-old virgin female CD1 mice (n = 22) were paired overnight with vasectomized males and successfully mated, indicated by the presence of a vaginal plug. These dams underwent embryo transfer 3 days later with embryos obtained from superovulated 4-week-old F1 (C57BL/6 × CBA) females. Non-invasive vaginal lavage was conducted immediately before transfer. Dams were killed 6 days after transfer and the uterus collected for histological analysis. Embryo implantation rate in mice was 96% when cytological analysis of the lavage samples signified dioestrus (n = 6), whereas the implantation rate was <15% (n = 16) when cytology signified other stages of oestrous. This simple, quick, non-invasive measure of receptivity was accurate and easily adopted and, when applied prospectively, will avoid unnecessary surgery and subsequent culling of non-suitable recipients, while maximizing the implantation potential of each recipient female.
The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Australia. Electronic address: jared.mamrot@hudson.org.au.
Jared
J
Mamrot
Department of Obstetrics and Gynaecology, Monash University, Clayton, Australia.
Mulyoto
M
Pangestu
The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Australia.
David
D
Walker
School of BioSciences, The University of Melbourne, Parkville, Australia.
David K
DK
Gardner
The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Australia; Department of Obstetrics and Gynaecology, Monash University, Clayton, Australia.
Hayley
H
Dickinson
D000818:Animals; D004031:Diestrus / Q000502:physiology*; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D011247:Pregnancy; D011555:Pseudopregnancy / Q000503:physiopathology*; D007507:Therapeutic Irrigation; D014599:Uterus / Q000033:anatomy & histology / Q000502:physiology; D014621:Vagina / Q000166:cytology / Q000502:physiology
blastocyst; mouse; optimization; pregnancy; recipient; smear