Intracytoplasmic sperm injection (ICSI)-mediated transgenesis in mice

Assisted Reproductive Techniques and Genetic Manipulation in the Common Marmoset

Genetic modification of nonhuman primate (NHP) zygotes is a useful method for the development of NHP models of human diseases. This review summarizes the recent advances in the development of assisted reproductive and genetic manipulation techniques in NHP, providing the basis for the generation of genetically modified NHP disease models. In this study, we review assisted reproductive techniques, including ovarian stimulation, in vitro maturation of oocytes, in vitro fertilization, embryo culture, embryo transfer, and intracytoplasmic sperm injection protocols in marmosets. Furthermore, we review genetic manipulation techniques, including transgenic strategies, target gene knock-out and knock-in using gene editing protocols, and newly developed gene-editing approaches that may potentially impact the production of genetically manipulated NHP models. We further discuss the progress of assisted reproductive and genetic manipulation techniques in NHP; future prospects on genetically modified NHP models for biomedical research are also highlighted.

A modified holding pipette for mouse oocyte fertilization

The safety of assisted reproductive technology (ART) is of frequent concern. Unfortunately, animal models for studying the safety of intracytoplasmic sperm injection (ICSI) have limitations in mimicking human ICSI manipulations. As reported herein, we invented a modified holding pipette for mouse oocyte injection that resulted in the delivery of live pups. A modified holding pipette was prepared for mouse oocyte injection and was compared with the conventional pipette for human use and a trumpet-shaped pipette. After ICSI, the oocytes were cultured to cleavage embryos until fallopian transfer. The use of the trumpet-shaped holding pipette and the new modified holding pipette for mouse oocyte injection achieved comparable and satisfactory oocyte survival rates (83.44% and 85.71%, respectively) and embryo cleavage rates (41.98% and 42.42%, respectively), which were significantly higher than those obtained with the human egg-holding pipette (oocyte survival rate: 65.85%; embryo cleavage rate: 27.78%). After 13 embryos were transferred using each type of pipette, three live pups were produced with the new modified holding pipette, one was produced with the holding pipette for human use, and none were produced with the trumpet-shaped holding pipette. The modified holding pipette for oocyte injection is effective and very easy to prepare. Moreover, using this new method, we produced live pups, which will contribute to a useful animal model for safety studies of ICSI in the future.