In vitro fertilization and development of mouse ova in protein-free medium

Abstract

Mouse ova were fertilized and developed in vitro in protein-free media. Superovulated ova from (JCL-ICR strain) female mice were fertilized in vitro by epidi-dymal sperm of the same strain and cultured for 114 h under 5% CO₂ in air and the sub sequent development of the fertilized ova was examined.
In the separate experiment, 2-cell embryos were flushed out of the oviducts of super-ovulated JCL-ICR mice 48 h after hCG injection and mating. The 2-cell embryos were cultured for 68 h and the subsequent development of the embryos was examined.
Fertilization rates judged from the second polar body extrusion at 6 h after insemina-tion were 28.3 (45/159), 26.8 (71/265) and 62.5% (60/96) in protein-free medium containing 0, 50 and 100 μm EDTA, respectively. The development rates of these fertilized ova to bla-stocyst stage were 0 (0/45), 53.5 (38/71) and 76.7% (46/60) after 114 h of culture in protein-free medium containing 0, 50 and 100 μm EDTA, respectively. The development rate of the late 2-cell embryos collected from the oviducts to blastocyst stage was 95.7% (45/47) after 68 h of culture in protein-free medium. From these findings, it is suggested that mouse ova can be fertilized and be developed in protein-free media.