SUMMARY
To investigate the significance of impaired insulin secretion on preimplantation embryo development, outbred ICR female mice received an injection of a single dose of streptozotocin 200 mg.kg-1 14-17 days before fertilization. Oocytes were collected 24-26 h after hCG injection. Morphological evaluation revealed a lower percentage of oocytes with second polar bodies from streptozotocin-treated females in comparison with controls. Furthermore, in this group the incidence of degenerated embryos significantly increased after in vitro 120 h cultivation. Insulin (5 U per 100 g b.w.) administered twice daily to streptozotocin-treated mice significantly improved the embryonic development. Morphological analysis of oocyte maturation in streptozotocin-treated mice showed no significant differences in comparison with control mice. It could be concluded that in outbred ICR mice marked changes in preimplantation embryo development were detected after streptozotocin administration and this process was partly reversible by insulin treatment. Furthermore, it was shown that the process of fertilization was negatively influenced and that during in vitro cultivation the delayed effects of impaired insulin secretion resulted in an increase of embryo degeneration at the time following the third mitotic cleavage.
Contact: Dr. Rehak