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Department of Theriogenology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Korea. ahnsnu2@snu.ac.kr |
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For parthenogenetic activation
as a model system of nuclear transfer, microinjection and electroporation
as activation treatments in bovine metaphase II oocytes were administered
to each of three groups as follows: control group (treatments with
Ca2+, Mg2+ -free PBS+100 micro M EGTA), IP3 group (control+25 micro
M IP3) and IP3+ ryanodine group (control+25 micro M IP3+10 mM ryanodine).
In experiments using microinjection, no significant differences
were observed between any of the developmental stages of the electroporation
experiment. For electroporation, cleavage rates were significantly
higher in the IP3+ryanodine group than in the IP3 or control group
(85.6% vs 73.7% or 67.6%, respectively). In the subsequent stages
of embryonic development, such as morula and blastocyst formation,
the IP3 and ryanodine group exhibited significantly higher rates
of morula fomation than the IP3 or control groups (40.6% vs 24.2%
or 16.7%, respectively). Similarly, the rate of blastocyst formation
in the IP3+ryanodine group was significantly higher than the control
group (16.3% vs 6.9%) but did not differ significantly from the
IP3 group (16.3% vs 9.5%). In nuclear transfer, activation was performed
at 30 hpm by microinjection and elecroporation with 25 micro M IP3+
10 mM ryanodine followed by 6-DMAP treatment. No significant differences
were observed at any stage of embryonic development and none of
the embryos activated by electroporation reached either the morula
or blastocyst stage. However, 3.8% and 1.9% of embryos activated
by microinjection sucessfully developed to the morula and blastocyst
stages, respectively. In conclusion, activation treatments using
IP3 and ryanodine are able to support the development of bovine
parthenogenetic and reconstructed embryos. |
