Confocal microscopic analysis of the spindle and chromosome configurations of human oocytes matured in vitro.
OBJECTIVE
To assess the potential effects of in vitro maturation (IVM) of human oocytes on the meiotic spindle and associated chromosome configuration.


METHODS
Prospective study.


METHODS
Hospital-based IVF center.


METHODS
Patients with polycystic ovary syndrome (PCOS) undergoing unstimulated and stimulated cycles of oocyte retrieval.


METHODS
Immature (germinal vesicle and metaphase I) and mature (metaphase II) oocytes were collected from PCOS patients. The meiotic spindle and chromosome configurations in oocytes matured in vitro and in vivo were studied by confocal microscopy, with fluorescent labeling techniques for visualization of both microtubules and chromatin.


METHODS
Meiotic spindle and associated chromosome configurations.


RESULTS
Oocytes can develop to the metaphase II stage after IVM. Confocal microscopic observations revealed that the oocytes matured in vitro had a higher frequency of abnormal meiotic spindle and chromosomal alignment morphology than in vivo-matured oocytes. These abnormalities included a partial or total disorganization of the meiotic spindle microtubules. Abnormal chromosome organization included dispersal of chromosomes or chromosomes with an aberrant, less-condensed appearance. The proportions of abnormality in spindle and chromosome configurations in oocytes matured in vitro were 43.7% and 33.3%, respectively, which was significantly higher than in those oocytes matured in vivo (13.6% and 9.1%).


CONCLUSIONS
In vitro maturation can have deleterious effects on the organization of the meiotic spindle and chromosome alignment of human oocytes. This result suggests one possible explanation for the reduced developmental potential of oocytes matured in vitro compared with those matured in vivo. This is likely a contributing factor to the overall lower clinical outcomes observed after IVM and ET.
Center for Reproductive Medicine, Shandong Provincial Hospital, Shandong University, Jinan, China.
Yuan
Y
Li
Huai-Liang
HL
Feng
Yi-Juan
YJ
Cao
Guang-Juan
GJ
Zheng
Yong
Y
Yang
Steve
S
Mullen
John K
JK
Critser
Zi-Jiang
ZJ
Chen
D000328:Adult; D002454:Cell Differentiation / Q000502:physiology; D002869:Chromosome Aberrations; D002877:Chromosomes, Human; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects / Q000379:methods; D006801:Humans; D018613:Microscopy, Confocal / Q000379:methods; D009865:Oocytes / Q000166:cytology* / Q000473:pathology; D009866:Oogenesis / Q000502:physiology; D011085:Polycystic Ovary Syndrome / Q000473:pathology / Q000628:therapy; D011446:Prospective Studies; D008941:Spindle Apparatus / Q000473:pathology