Effects of in vitro maturation and age on oocyte quality in the rhesus macaque Macaca mulatta.
OBJECTIVE
To evaluate oocyte quality in a primate model.


METHODS
Analysis of oocyte karyotype by chromosome spreading and oocyte spindles by confocal microscopy.


METHODS
Research laboratory, Caribbean Primate Research Center.


METHODS
Rhesus macaques aged 6-22 years.


METHODS
Fourteen females underwent both Regimen A (FSH + hCG) and Regimen B (FSH only) stimulation cycles to facilitate collection of mature and immature oocytes. Immature oocytes from Regimens A and B underwent in vitro maturation (IVM) to produce metaphase II oocytes. All metaphase II oocytes underwent gradual fixation to spread chromosomes or were fixed and stained with probes specific to alpha-tubulin, actin, and DNA for visualization of the meiotic spindle using confocal microscopy.


METHODS
Karyotype and meiotic spindle architecture differences among in vivo matured (IVO) and IVM oocytes from young and old rhesus macaques.


RESULTS
In all, 4.7% of IVO oocytes (Regimen A) from young females were hyperhaploid versus 25.0% of IVM oocytes (Regimen B) from old females; 4.5% of IVO oocytes (Regimen A) from young females versus 51.5% of IVM oocytes (Regimen B) from old females displayed abnormal chromosome alignment on the metaphase spindle.


CONCLUSIONS
IVM can induce meiotic anomalies in macaque oocytes, especially those obtained from older females. Results from this study provide possible explanations for the reported reduction in developmental competence of IVM primate oocytes.
Nichols
Stephanie M
SM
Reproductive Biology Program, Caribbean Primate Research Center, Unit of Comparative Medicine, University of Puerto Rico, P.O. Box 1053, Sabana Seca 00979, Puerto Rico. snichols@rcm.upr.edu
Gierbolini
Lynette
L
Gonzalez-Martinez
Janis A
JA
Bavister
Barry D
BD
D000367:Age Factors; D000375:Aging; D000782:Aneuploidy; D000818:Animals; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D005260:Female; D007150:Immunohistochemistry; D007621:Karyotyping; D008253:Macaca mulatta; D008677:Metaphase; D018613:Microscopy, Confocal; D009865:Oocytes / Q000648:ultrastructure*; D010062:Ovulation Induction; D008941:Spindle Apparatus / Q000648:ultrastructure*