Deep freezing of sheep embryos

• Published in: Journal of reproduction & fertility Vol. 46; no. 1; pp. 151 - 154
• Main Authors: Willadsen, S M, Polge, C, Rowson, L E, Moor, R M
• Format: Journal Article
• Language: English
• Published: England 01.01.1976
• Subjects: Animals; Dimethyl Sulfoxide - pharmacology; Embryo Transfer; Embryo, Mammalian - cytology; Embryo, Mammalian - drug effects; Female; Freezing; Rabbits; Sheep - embryology; Temperature; Tissue Preservation - methods; Transplantation, Heterologous; Transplantation, Homologous
• ISSN: 0022-4251; 1470-1626; 1741-7899
• DOI: 10.1530/jrf.0.0460151

Sheep embryos, collected 1-8 days after oestrus, were placed in Dulbecco's phosphate-buffered saline medium (PBS). After treatment, the viability of the embryos was tested by temporary transfer to ligated rabbit oviducts. In Exp. 1, Days 5-8 embryos survived for at least 15 min at 0 degrees C in the presence of 1-5 M-DMSO. In Exp. 2, 12/14 Days 5-8 embryos survived after being frozen in 1-5 M-DMSO at 0-3 degrees C/min to temperatures ranging between-15 degrees and -60 degrees C and then thawed at 12 degrees C/min. In Exp. 3, Days 5-8 embryos were frozen in 1-5 M-DMSO at 0-3 degrees C/min to below-65 degrees C before being transferred to liquid nitrogen (-196 degrees C), and stored for 12 hr to 1 month. The embryos were thawed at 3 degrees C/min, 12 degrees C/MIN or 360 degrees C/min and, after transfer to rabbit oviducts, 0/4, 10/36 and 1/4, respectively, developed normally. The 11 embryos which were considered normal when recovered from the rabbit oviducts plus 1 slightly retarded embryo were transferred to 7 recipient ewes. Four ewes subsequently lambed, producing 5 lambs. In addition, 8 embryos were transferred to 4 ewes directly after thawing. Three of these ewes subsequently lambed, producing 3 lambs.