Pre-implantation developmental potential from in vivo and in vitro matured mouse oocytes: a cytoskeletal perspective on oocyte quality.
OBJECTIVE
In the present study, fertilization and developmental potential of mouse oocytes matured in different conditions were tested. The efficiency of in vitro fertilization (IVF), pre-implantation development and some important aspects of cytokinesis during early cleavages are discussed.


METHODS
In vivo matured (IVO), in vitro matured (IVM) and roscovitine-treated (IVM-Rosco) mouse oocytes were subjected to IVF under identical conditions. Three replicates per group were analyzed. Fertilization was identified by the presence of two pronuclei at 6-8 h post-fertilization. Evaluation of pre-implantation embryonic development was done daily from day 2 to day 5 and embryos were processed for analyses of chromatin, nuclear lamina, microtubules and centrosomal proteins by conventional and confocal fluorescence microscopy.


RESULTS
Both IVM groups displayed lower fertilization rates when compared to in vivo controls. While IVO-derived embryos exhibit efficient and synchronous progression to the blastocyst stage, both IVM-derived embryos exhibit a delay in embryonic progression, and a lower blastocyst rate. Interestingly, IVM-Rosco M-II oocytes exhibited more blastomere symmetries and higher number of cells at the blastocyst stage than the IVM group with the most notable influence being on the centrosome-microtubule complex of blastomeres.


CONCLUSIONS
Our study strongly indicates that when compared to spontaneously in vitro matured oocytes, treatment with roscovitine may partially enhance developmental competence by maintaining coordination between nuclear and cytoplasmic events. Further evidence is given of cytoskeletal biomarkers that can be identified during in vitro oocyte maturation conditions.
Faculdade de Medicina Veterinária, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024, Lisbon, Portugal.
Alexandra
A
Sanfins
Carlos E
CE
Plancha
David F
DF
Albertini
D000818:Animals; D001755:Blastocyst / Q000187:drug effects; D001757:Blastomeres / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000502:physiology; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D059471:In Vitro Oocyte Maturation Techniques; D066298:In Vitro Techniques; D051379:Mice; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development*; D011247:Pregnancy; D011687:Purines / Q000008:administration & dosage; D000077546:Roscovitine
D011687:Purines; D000077546:Roscovitine