Effect of Cytochalasin B on Survivability and in Vitro Development of Mouse Oocyte Frozen by Vitrification

Choi, Won Jun; Lee, Soon Ae; Lee, Jong Hak; Paik, Won Young

Abstract

OBJECTIVE
The purpose of this study was to evaluate the effect of CCB treatment on the survivability and in vitro development of mouse oocyte frozen by vitrification.
METHODS
Mouse oocytes retrieved from cycle stimulated by PMSG and hCG were treated by CCB and then exposed to EFS-30. These oocytes were placed onto an EM grid and submerged immediately in liquid nitrogen. Thawing of the oocytes on EM grid was carried out at room temperature for 5 seconds, then the EM grid was placed into 0.75 M sucrose at 37degrees C for 3 minutes. This was followed by 0.5 M and 0.25 M sucrose for 3 minutes, each. We compared the survivability, cleavage and developmental rate of mouse frozen by vitrification between CCB treated and non-treated groups. Chi-square was used to determine statistical significance. statistical significance was defined as p<0.05.
RESULTS
Survivability (79.3%) and developmental rate into blastocyst (52.3%) of mouse oocyte were markedly decreased after vitrification. There were no significant differences between CCB treated and non- treated groups regarding survivability of oocyte frozen by vitrification (80.3% vs 78.5%). The developmental rate into 2-cell in CCB treated group was significantly higher than that in non-treated group (69.7% vs 61.9%, p<0.05). The developmental rate into blastocyst in CCB treated group was higher than that in non-treated group (54.9% vs 51.5%), but the difference was not significant.
CONCLUSION
Survivability of mouse oocyte could not be affected by CCB treatment and developmental rate into 2-cell was improved in CCB treated group. It is suggested that CCB treatment prior vitrification improve stability of cytoskeleton and then improve fertilization and early stage embryo development.