Effect of Culture Medium Volume on the Development and Viability of Microinjected or Noninjected One-Cell Hybrid and CD-1 Strain Mouse Embryos

We investigated the effects of drop volume on the development of mouse presumptive zygotes to the completely hatched blastocyst stage. For this aim, we established 3 experimental groups. In the first group, we cultured hybrid presumptive zygotes to the hatched blastocyst stage in 10 presumptive zygotes per 5, 10, 20, 40 and 50 µl drops. In the second group, we used microinjected hybrid zygotes for culture. In the last group, we cultured CD-1 mouse presumptive zygotes to the hatched blastocyst stage. There was no statistical difference in the first group. In contrast, the data demonstrated that there were significant differences in the second and third groups. We also determined the cell number of blastocyst stage embryos in each group and evaluated the results statistically. In conclusion, although the development rate of hybrid mouse zygotes to the hatched blastocyst stage was the highest in 5 µl culture drops, the highest blastocyst cell number was achieved in 40 µl. The highest rates for the development to the hatched blastocyst stage and the blastocyst cell number were also obtained in 40 µl culture drops for microinjected hybrid zygotes. In the CD-1 strain, the highest cell number was obtained in 10 µl. It is clear from the present study that it is important to consider the culture medium volume as a crucial factor affecting the in vitro development of pre-implantation embryos. The genetic background and the manipulation process such as pronuclear microinjection of the zygotes could influence their in vitro developmental potential in terms of medium volume.