Scanning electron microscopic findings of cleaved unfertilized eggs ovulated by repeated administration of gonadotrophin

Oocytes in the degenerative process are suggested to be rescued and to developed to ovulation by repeated induction of superovulation using gonadotrophin (GTH). In this study, the morphology of abnormally cleaved unfertilized eggs obtained by repeated induction of superovulation in mice using PMSG/hCG was observed by scanning electron microscope. As a result, loss of microvilli was noted on the cell surface of cleaved unfertilized eggs. On the other hand, ample microvilli were observed on the cell surface of fertilized eggs in the morula stage obtained 65 hours after spontaneous copulation used as controls. Loss of microvilli on the cell surface is a characteristic finding in apoptotic cells. Cleaved unfertilized eggs obtained by repeated induction of superovulation using GTH are considered to be in the degenerative process due to apoptosis.