Effects of cyclophosphamide administration on the in vitro fertilization of mice

PurposeTo evaluate the oocyte fertilization ability and embryo growth after cyclophosphamide (CPA) treatment in mice. MethodsMice were treated with CPA at different doses (0-800mg/kg body weight). The oocytes then were retrieved and evaluated for their in vitro fertilization efficiency. ResultsThe average number of metaphase II (MII) oocytes significantly decreased by 400mg/kg CPA administration. The fertilization rate also decreased in the group that was treated with 400mg/kg CPA. However, after fertilization, the embryos demonstrated normal growth ability. Two weeks after CPA administration, the number of mice from which the oocytes could be retrieved markedly decreased, but the fertilization rate and development of morphological features in the embryos were similar to those of the controls. One month after CPA administration, the number of mice from which the oocytes could be retrieved, fertilization rate, and development of the morphological features in the embryos were similar to those of the controls. ConclusionThe number of oocytes decreased as the CPA administration level increased; however, the oocytes' potential for fertilization and development to the blastocyst stage was not significantly affected. One month after CPA administration, the number of oocytes and the potential for development into blastocysts were recovered.