Ultrastructural changes of corpus luteum after ovarian stimulation at implantation period

To achieve multiple oocytes for in vitro fertilization, ovulation induction is induced by gonadotropins; however, it has several effects on oocytes and embryo quality and endometrium receptivity. The aim of this study was to assess ultrastructural changes of corpus luteum after ovarian induction using human menopausal gonadotropin [HMG] and human chorionic gonadotropin [HCG] during luteal phase at implantation period. Female NMRI mice [6-8 weeks] were divided into control and stimulated groups. In the control group, the mice were rendered pseudopregnant and in the ovarian induction group, the mice were rendered pseudopregnant after the ovarian induction. The samples were obtained from the ovary in each group at the same time during luteal phase at implantation period. Ultrastructural changes were assessed using electron microscopy study. Our results displayed some identifiable changes in ultrastructure of corpus luteum in ovarian induction group. These changes included enhancement of the apoptosis and intercellular space, whereas the angiogenesis was decreased. The findings indicated a decline in organelle density in the cytoplasm of ovarian induction, such as mitochondria, endoplasmic reticulum and polyribosome. Furthermore, chromatin condensation of nuclei was observed in some cells. The ovarian induction using HMG and HCG resulted in some ultrastructural changes on the corpus luteum at implantation period, which could affect on the pregnancy rate

Effect of ovarian stimulation on the endometrial apoptosis at implantation period

Apoptosis is a process that plays an important role during early stage of implantation. The aim of this study was to investigate the incidence of apoptosis in mice endometrium after ovarian stimulation at implantation period. NMRI female mice were divided into two groups: 1] control group, which were rendered pseudopregnant by vaginal stimulation and 2] experimental group, which were stimulated using an intrapritoneal injection of 10 IU hMG followed by another injection of 10 IU hCG after 48 h. In the evening of the second injection, the mice were rendered pseudopregnant the same as control group. Samples were obtained from 1/3 middle part of uterine horns during implantation period. Apoptosis was assessed in two groups at implantation period using light and electron microscopic studies, TUNEL staining and semiquantitative RT-PCR. Our morphological and ultrastructural results showed apoptosis in both groups, while TUNEL analysis showed that the percentage of TUNEL-positive cells was higher in stimulated group than in the control group [P