Use of the Artificial Zona Pellucida Made of Calcium Alginate in the Development of Preimplantation Mouse Embryo.

Using calcium alginate as material for the artificial zona pellucida, the early embryonic development and the implantation of zona-free mouse eggs encapsulated with an artificial zona pellucida were investigated. In the group of two-cell embryos encapsulated with the artificial zona pellucida, 95.0% developed to the blastocyst. On the other hand, 93.1% in the zona intact group and 83.0% in the zona free group developed to the bla-stocyst. The rate of the embryo encapsulated with an artificial zona pellucida developing to the blastocyst was significantly higher than that in the non-capsulated zona-free embryo (P<0.05) and also exceeded that in the zona intact embryo. Twelve normal fetuses were obtained after the transfer of 75 blastocysts encapsulated with the artificial zona pellucida to recipients. These results indicates that calcium alginate used as an artificial zona pellucida is not detrimental to the development of the embryos but plays a protective role in the preimplantation embryo development, and the artificial zona pellucida dissolves timely in the uterus and dose not hinder implantation. If hardness of calcium alginate suitable for humans can be found, clinical application of IVF-ET with zona-free eggs making use of an artificial zona pellucida will become possible.