Mohammed Abd El-Nasser Ahmed, Al-Suwaiegh Saker, Al-Shaheen Tarek
1Department of Animal & Fish Production, College of Agriculture and Food Sciences, King Faisal University, Al-Ahsaa, Saudi Arabia.
2Department of Animal Production, Faculty of Agriculture, Assiut University, Assiut, Egypt.
Cell Reprogram. 2019 Aug;21(4):163-170. doi: 10.1089/cell.2019.0032. Epub 2019 Jul 16.
Maturation conditions and oocytes quality have substantial roles on developmental competence of unreconstructed or reconstructed oocytes. Cloning has been reported successfully with low efficiency through embryonic or somatic nuclear transfer into enucleated metaphase II oocytes. It has been suggested that introducing embryonic or somatic nucleus to cytoplast at earlier stage might improve reprogramming of the introduced nucleus. In addition, the synchronization between the donor nucleus and recipient cytoplasts might effect on reprogramming and further embryonic development. Therefore, the question arises; does the cytoplast of germinal vesicle (GV) oocyte containing nuclear sap improve developmental competence upon reconstruction with embryonic/somatic nucleus compared with MII cytoplast. It has been indicated that GV material is essential for remodeling of sperm or embryonic or somatic nucleus in GV oocyte cytoplast and their further embryonic developmental competence. GV cytoplasts could be obtained through micromanipulation. Different micromanipulation techniques of immature oocytes at different stages were adapted in addition to introducing donor nuclei at G0/G1, S and G2/M phase, and enucleolation technique as well. Upon micromanipulation, it could obtain GV cytoplasts; cumulus-free and without GV material, cumulus-complexes and without GV material, cumulus-free and with GV material, and cumulus-complexes and with GV material in addition to enucleolated GV oocytes. Therefore, this short review will address briefly the importance of maturation conditions, cumulus cells, oocyte quality, the techniques of enucleation GV oocyte, the cell cycle stage of the introduced donor cell, or nucleus for oocyte maturation and embryo development.
成熟条件和卵母细胞质量对未重构或重构卵母细胞的发育能力具有重要作用。据报道，通过将胚胎或体细胞核转移到去核的中期II卵母细胞中，克隆已成功实现，但效率较低。有人提出，在更早阶段将胚胎或体细胞核引入细胞质可能会改善引入细胞核的重编程。此外，供体细胞核与受体细胞质之间的同步可能会影响重编程和进一步的胚胎发育。因此，问题就出现了：与MII细胞质相比，含有核液的生发泡（GV）卵母细胞的细胞质在与胚胎/体细胞核重构后是否能提高发育能力。已经表明，GV物质对于GV卵母细胞细胞质中精子、胚胎或体细胞核的重塑及其进一步的胚胎发育能力至关重要。GV细胞质可以通过显微操作获得。除了在G0/G1、S和G2/M期引入供体细胞核以及去核技术外，还采用了不同阶段未成熟卵母细胞的不同显微操作技术。通过显微操作，可以获得无卵丘且无GV物质、有卵丘复合体且无GV物质、无卵丘且有GV物质、有卵丘复合体且有GV物质的GV细胞质，以及去核的GV卵母细胞。因此，这篇简短的综述将简要阐述成熟条件、卵丘细胞、卵母细胞质量、GV卵母细胞去核技术、引入的供体细胞或细胞核的细胞周期阶段对卵母细胞成熟和胚胎发育的重要性。
