A COMPARISON OF THE CELL-KINETICS OF PRE-IMPLANTATION MOUSE EMBRYOS FROM 2 DIFFERENT MOUSE STRAINS

  • 1 January 1983
    • journal article
    • research article
    • Vol. 16  (3) , 277-283
Abstract
The progression of preimplantation mouse embryos through the 1st, 2nd and 3rd embryonic cell cycle was investigated cytofluorometrically. In contrast to most of the previous studies, the ova were spontaneously ovulated and the mating period of the ova donors was short (06.00-0.900 h). The embryonic cells proceeded through the 1st, 2nd and 3rd cell cycle as a cohort. Thus, it was possible to estimate the duration of the cell cycle phases directly from the DNA histograms. The length of the cell cycle phases differed between the embryos of the 2 different mouse strains. The most pronounced differences were found for the G2 + M phases (1st cell cycle: 8 h for strain I and 5 h for strain II; 2nd cell cycle: 11.5 h and 14 h, respectively). In accordance with previous investigations, common features of the early preimplantation cell kinetics were also observed; increasing length of the S phases from the 1st to the 2nd cell cycle and very short G1 phases in the 2nd and 3rd cell cycle. The cell proliferation of the embryos of both strains after the 3rd cell cycle was characterized by exponential growth. The proliferation rate was higher in strain I embryos than in strain II embryos (steeper increase of the growth curve). At the end of the preimplantation development (hatched blastocysts), the growth curves of both strains decreased. The differences concerning the durations of the cell cycle phases and the proliferation rates are considered to be strain specific. The differences in the preimplantation cell kinetics which have been described generally reflect the strain specificities more than different investigational methods and/or different grades of synchrony of early preimplantation embryos.