title: The crucial role of zona pellucida in cryopreservation of oocytes by vitrification.
abstract: Mammalian oocytes have a proteinaceous hydrogel-like outer shell known as the zona pellucida (ZP) that semi-encloses their plasma membrane and cytoplasm. In this study, we cryopreserved mouse oocytes either with or without ZP by vitrification. Our results show that the presence of an intact ZP could significantly improve the post-vitrification survival of oocytes to 92.1% from 13.3% for oocytes without ZP. Moreover, there was no significant difference in embryonic development between fresh and cryopreserved oocytes with ZP after in vitro fertilization (IVF). Further atomic force microscopy (AFM) analysis showed that the intact oocytes with ZP have an elastic modulus that is more than 85 times higher than that of oocytes without ZP. This may partially explain the important role of ZP in protecting the oocytes by resisting the mechanical stress due to possible ice formation during cryopreservation by vitrification. Collectively, this study reveals a new biophysical role of ZP during vitrification of oocytes and suggests microencapsulation of the many mammalian cells without a ZP in ZP-like hydrogel is an effective strategy to improve their survival post cryopreservation by vitrification.
authors: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, United States; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, United States.
authors: Jung Kyu
authors: JK
authors: Choi
authors: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, United States.
authors: Tao
authors: T
authors: Yue
authors: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, United States; Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210, United States.
authors: Haishui
authors: H
authors: Huang
authors: Center for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui 230027, China.
authors: Gang
authors: G
authors: Zhao
authors: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, United States; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, United States.
authors: Mingjun
authors: M
authors: Zhang
authors: Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, United States; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, United States; Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, United States. Electronic address: He.429@osu.edu.
authors: Xiaoming
authors: X
authors: He
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods*; D055119:Elastic Modulus / Q000502:physiology; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D018625:Microscopy, Atomic Force; D009865:Oocytes / Q000166:cytology*; D010542:Peromyscus; D013314:Stress, Mechanical; D058989:Vitrification; D015044:Zona Pellucida / Q000502:physiology*
keywords: AFM; Cryopreservation; Oocyte; Vitrification; Zona pellucida