Method and culture medium for preparing mammalian ovum or embryo in which zona pellucida has been thinned or eliminated, and method for fertilization using mammalian ovum prepared by same method
Provided are a method for preparing a mammalian ovum or embryo in which zona pellucida has been thinned or eliminated, and a method for fertilization using the mammalian ovum prepared by the aforementioned method. The method for thinning or eliminating zona pellucida of a mammalian ovum or embryo involves treating or culturing the mammalian ovum or embryo (such as an unfertilized ovum, a fertilized ovum, or an embryo in the early stages of development) in a culture medium containing a reducing agent having SH groups (such as reduced glutathione or DTT). The resulting mammalian ovum or embryo (such as an unfertilized ovum, a fertilized ovum, or an embryo in the early stages of development) in which zona pellucida has been thinned or eliminated is capable of realizing an improved fertilization rate and development rate when used for in vitro fertilization, transplantation of a fertilized ovum, or preparation of an embryo in the early stages of development used in the production of a genetically modified animal.