Conventional Freezing, Straw, and Open-Pulled Straw Vitrification of Mouse Two Pronuclear (2-PN) Stage Embryos

• Published in: Animal biotechnology Vol. 18; no. 3; pp. 203 - 212
• Main Authors: Zhao, Xue-Ming, Quan, Guo-Bo, Zhou, Guang-Bin, Hou, Yun-Peng, Zhu, Shi-En
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01.01.2007
• Subjects: Animals; Conventional freezing; Cryopreservation - veterinary; Cryoprotective Agents; Dimethyl Sulfoxide; Embryo Transfer - veterinary; Ethylene Glycol; Female; Ficoll; Male; Mice - embryology; Morula; Mouse; Open-pulled straw (OPS); Pregnancy; Sucrose; Two-pronuclear embryo; Vitrification
• ISSN: 1049-5398; 1532-2378
• DOI: 10.1080/10495390701201663

Little is known on the cryopreservation of mouse pronuclear (PN) stage embryos. In the present experiment the mouse 2-PN stage embryos were cryopreserved by conventional freezing, straw, or open-pulled straw (OPS) vitrificaiton methods. The conventional freezing solution was 1.5 mol/L ethylene glycol (EG), and vitrification solutions were EFS30 (30% EG, Ficoll, and sucrose), EFS40 (40% EG, Ficoll, and sucrose), EDFS30 (15% EG, 15%dimethyl sulfoxide [DMSO], Ficoll, and sucrose), or EDFS40 (20% EG, 20%DMSO, Ficoll, and sucrose). The blastocyst rate of 2-PN stage embryos cryopreserved by conventional method (30.4%) was lower than those vitrified by straw method with EDFS (56.9% to 69.1%), by OPS method (66.0% to 85.7%), and that of control (80.8%) (P < 0.05). With a given vitrificaiton solution EFS30, EFS40, EDFS30, or EDFS40, the blastocyst rate of embryos vitrified by the OPS method (66.7%, 66.0%, 85.7%, or 76.9%) was higher than that of those vitrified by the straw method (46.8%, 43.8%, 69.1%, or 56.9%) (P < 0.05). When mouse 2-PN-stage embryos were vitrified with EDFS30 by straw or OPS method, the highest blastocyst rate was achieved (69.1% or 85.7%) and was similar to that of the control, respectively. The embryos transfer results revealed that the full-term development of blastocysts derived from 2-PN stage embryos vitrified by OPS method with EDFS30 (19.9%) was similar to that of the control (23.5%), and higher than that of those cryopreserved by conventional freezing (9.3%) (P < 0.05). The present research demonstrates that the OPS method, especially with EDFS30, is more effective in cryopreserving mouse 2-PN embryos.