title: An attempt of cryopreservation of mouse embryos at the ACTREC laboratory animal facility in India.
abstract: Cryopreservation is the long-term storage of viable cells/tissue in liquid nitrogen. The present study was conducted to freeze 8-cell- to morula-stage mouse embryos from the ACTREC Laboratory Animal Facility using a "slow freezing and fast revival" method. In all, 4,088 embryos were collected from 495 donor female mice of ten different strains. An average recovery of 8 embryos per donor mouse were recorded. Of the 4,088 embryos, 3,946 embryos of normal morphology were frozen in 173 straws. They were cooled down using a controlled-rate freezing assembly, and the straws were directly plunged into liquid nitrogen for long-term storage. Out of these 3,946 frozen embryos, 2,650 were found to be viable after fast revival. The highest survival rate, 81%, was recorded in B6D2F1 hybrid mice, whereas the lowest rate, 51%, was recorded in the S/RV/Cri-ba mutant strain. Out of 2,650 viable embryos, 2,359 embryos (89%) developed to the blastocyst stage after 24 h of incubation in a CO(2) incubator. The developed blastocysts were transferred surgically into 101 pseudopregnant female mice, of which 49 (48.5%) females were found to be pregnant. The highest percentage of pregnancy, 75%, was recorded in C57BL/6NCrl and NIH-III mice, whereas no pregnant recipients were recorded in Ptch, C3H/HeNCrl and NOD SCID mice. Based on the deliveries of these 49 females, an average of 4 young were delivered per female. Improvement in efficiency of freezing, thawing, and surgical transfer of embryos into pseudopregnant females is one of the challenges in such studies.
authors.affiliation: Laboratory Animal Facility, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai- 410 210, India.
authors.forename: Rahul
authors.initials: R
authors.lastname: Thorat
authors.forename: Arvind
authors.initials: A
authors.lastname: Ingle
mesh_terms: D000818:Animals; D000830:Animals, Laboratory / Q000502:physiology*; D001755:Blastocyst / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D046149:Embryo Culture Techniques; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000502:physiology*; D005260:Female; D005615:Freezing; D050498:Live Birth; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D011247:Pregnancy; D011555:Pseudopregnancy