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Published on: April 26, 2018
Comparison of oocyte-activating agents for mouse cloning
H Kishikawa1, T Wakayama, R Yanagimachi
1Department of Anatomy and Reproductive Biology, University of Hawaii Medical School, Honolulu, Hawaii, USA. kishi@uro.med.osaka-u.ac.jp
Abstract:
Since somatic cell components are unable to activate oocytes following injection or fusion, enucleated oocytes receiving adult somatic cells during the cloning process must be activated artificially for their development. We compared the efficiency of four types of oocyte-activating agents: strontium, ethanol, single electric pulse, and spermatozoa. Although strontium was the best in supporting preimplantation development of reconstructed mouse oocytes, there was no significant difference among the four agents with respect to the rate of postimplantation embryo development and the birth of live offspring.
Insights
Artificial oocyte activation is crucial for cloning. While strontium best supported early mouse embryo development, all tested agents (strontium, ethanol, electric pulse, sperm) yielded similar postimplantation and live birth rates.
Area of Science:
- Reproductive biology
- Developmental biology
- Somatic cell nuclear transfer
Background:
- Somatic cells cannot naturally activate oocytes after injection or fusion.
- Artificial oocyte activation is essential for the development of cloned embryos.
- Reconstructed oocytes require activation to initiate development.
Purpose of the Study:
- To compare the efficiency of four different oocyte-activating agents.
- To evaluate the impact of activation methods on reconstructed mouse oocyte development.
- To determine the optimal agent for supporting embryo development post-cloning.
Main Methods:
- Enucleated oocytes were reconstructed with adult somatic cells.
- Four activation agents were tested: strontium, ethanol, single electric pulse, and spermatozoa.
- Developmental rates, including preimplantation, postimplantation, and live birth, were assessed.
Main Results:
- Strontium demonstrated superior support for preimplantation development of reconstructed mouse oocytes.
- No significant differences were observed among the four agents regarding postimplantation embryo development.
- The rates of live offspring did not significantly differ across the tested activation agents.
Conclusions:
- While strontium enhances early embryo development, its long-term benefits are comparable to other agents.
- The choice of oocyte-activating agent does not significantly impact postimplantation development or live birth rates in mouse cloning.
- Further research may explore synergistic effects or alternative activation protocols for improved cloning efficiency.
