
%0 Journal Article
%A Ock, S.-A. 
%A Rho, G.-J. 
%T 232 PARTHENOGENETIC DEVELOPMENT AND PLOIDY OF BOVINE OOCYTES FOLLOWING VARIOUS CHEMICAL ACTIVATION REGIMENS
%J Reproduction, Fertility and Development
%D 2007/12/12
%V 20
%N 1
%P 195-196
%K 
%R https://doi.org/10.1071/RDV20N1AB232
%U https://www.publish.csiro.au/paper/RDV20N1AB232 
%X Bovine oocytes treated using various combinations of ionomycin (Ion), cycloheximide (CHX), and cytochalasin B (CCB) were evaluated for developmental rates and ploidy status. Metaphase II oocytes were allocated 5 treatment groups, and the groups were treated as follows: Group 1: 5 &#181;m Ion for 5 min; Group 2: Ion + 10 &#181;g mL&#8211;1 CHX for 5 h; Group 3: Ion + 10 &#181;g mL&#8211;1 CHX + 5 &#181;g mL&#8211;1 CCB for 1 h + 10 &#181;g mL&#8211;1 CHX for 4 h; Group 4: Ion + 10 &#181;g mL&#8211;1 CHX + 5 &#181;g mL&#8211;1 CCB for 3 h + 10 &#181;g mL&#8211;1 CHX for 2 h; and Group 5: Ion + 10 &#181;g mL&#8211;1 CHX + 5 &#181;g mL&#8211;1 CCB for 5. Difference among groups was analyzed using one-way ANOVA by SPSS 10.0 (SPSS, Inc., Chicago, IL, USA). In Experiment 1, 430 oocytes in 4 replicates were compared for the extrusion rate of the second polar body (PB) at 8 h after Ion treatment among groups. Group 5 exhibited significantly (P  < 0.05) lower rates of second PB extrusion than did Groups 1&#8211;4 (22% v. 53&#8211;67%). Experiment 2 compared the rates of cleavage at 48 h and development to the blastocyst stage at 216 h after Ion treatment among groups. A total of 536 oocytes were used in 5 replicates. Parthenotes in Group 1 showed lower rates of cleavage and blastocyst development than those in other groups (20% and 1% v. 53&#8211;67% and 6&#8211;31%). Among the groups, parthenotes in Group 5 showed significantly (P  < 0.05) higher blastocyst development. In Experiment 3, at 8 h after Ion treatment, oocytes from Groups 2, 3, and 5 were divided into two subgroups based on the presence or absence of the second PB, and assessed for cleavage rates and ploidy in 239 2-cell-stage parthenotes in 4 replicates, as described earlier by King et al. (1979 Vet. Sci. Commun. 3, 51&#8211;56). The cleavage rates did not differ among activation treatments, or by the presence or absence of the second PB in any activation group. The haploid rate was significantly (P  < 0.05) higher in Group 2 than in Groups 3 and 5 (38% v. 19% and 0%, respectively). The diploid rate was significantly (P  < 0.05) higher in Group 5 than in Groups 2 and 3 (88% v. 69% and 45%, respectively). In Experiment 4, the diploid rate of Group 2 blastocyst-stage parthenotes was 100% (4/4), whereas the diploid rates of Groups 3 and 5 blastocyst-stage parthenotes were 50% (6/12) and 71% (17/24), respectively, but the rates did not differ among groups. These results indicate that oocyte activation by CHX/CCB for 5 h after Ion treatment could enhance parthenogenetic development in bovines with higher rates of diploidy by preventing the extrusion of the second PB. 
