| Abstract: | Objective: To investigate the effect of Cytochalasin B(CCB) on the spindle and chromosome configuration of human in vitro matured oocytes after vitrification.Methods: Immature oocytes which were collected in intracytoplasmic sperm injection (ICSI) cycles (including stage GV and M I )after ovarian stimulation, followed in vitro matured(IVM) for 24-48 h. 170 oocytes were matured according to the extrusion of first polarbody, were randomized into five groups for vitrification. Group A:37 oocytes were treated with CCB for 20 mins before vitrification; Group B:38 oocytes with CCB for 30 mins; Group C:33 oocytes with CCB for 40 mins. Group D:36 oocytes without CCB before vitrification. Group E:26 ooctyes whitout vitrification and CCB as the controlled group. 71 in vivo matured oocytes were collected after ovarian stimulation in in vitro fertilization-embryo transfer (IVF-ET) cycles and ICSI cycles, and randomized into four groups for vitrification. Group A1:17 oocytes treated with CCB for 20 mins before vitrification; Group B1:20 oocytes with CCB for 30 mins. Group C1:17 oocytes with CCB for 40 mins. Group D1:17 oocytes without CCB before vitrification. All the oocytes were thawed after three weeks and then immunoftuorescence staining were perforned for tubu-lin and chromatin and at last visualized by confocal laser scanning microscopy.Results: There are no significant differences of survival rates among group A, B, C, D (80.39%, 64.86%, 55.36% and 78.79%, P>0.05) and group A1, B1, C1, D1 (64.7%, 50.0%, 64.7% and 70.6%, P>0.05). There are no significant differences in the frequencies of normal spindle and chromosome in group A, B, C, D (21.05%, 26.3%, 27.78% and 23.81%, P>0.05), but significantly lower than group E (61.54%, P<0.05). There were no significant differences in the frequencies of normal spindle and chromosome in group A1, B1, C1, D1 (27.3%, 30.0%,45.5% and 33.3%, P>0.05). No statistical differences were found in survival rate and frequencies of normal spindle and chromosome between in vitro matured groups treated with CCB and in vivo matured groups after vitrification (P>0.05).Conclusion: Spindle and chromosome configuration of human in vitro matured oocytes was damaged in vitrification, which can not improved by CCB pre-treatment before vitrification. Oocytes in vitro matured or in vivo matured have the same tolerance to the cryoinjury. |
