冷凍卵子可能對於紡垂體造成某種程序之傷害

紡垂體於慢速冷凍解凍過程一度消失
解凍過程後再予以重組
冷凍卵子仍可能對於卵子紡垂體造成某種程序之傷害

http://humrep.oxfordjournals.org/content/19/3/655.long

Polscope analysis of meiotic spindle changes in living metaphase II human oocytes during the freezing and thawing procedures

1. L. Rienzi1,3, 
2. F. Martinez1, 
3. F. Ubaldi1, 
4. M.G. Minasi1, 
5. M. Iacobelli1,
6. J. Tesarik2 and 
7. E. Greco1

+Author Affiliations

1. ¹Centre for Reproductive Medicine, European Hospital, Via Portuense 700, 00149 Rome, Italy and
2. ²MAR&Gen, Molecular Assisted Reproduction & Genetics, Granada, Spain

1. 3To whom correspondence should be addressed. e‐mail: rienzi.laura@libero.it

• Received May 30, 2003.
• Revision received October 21, 2003.
• Accepted October 31, 2003.

 

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Abstract

BACKGROUND: The clinical efficacy of the current methods used for cryopreservation of metaphase II human oocytes is low. Meiotic spindle disorders are thought to be largely responsible for this situation. METHODS: Supernumerary fresh metaphase II human oocytes were cryopreserved in 1,2‐propanediol with 0.1 M sucrose using a slow freezing/rapid thawing programme. Meiotic spindles were analysed in these living metaphase II oocytes at sequential steps of the freezing and thawing procedures with the use of a computer‐assisted polarization microscopy system (Polscope). RESULTS: The meiotic spindle was detected in all 56 oocytes (from 16 patients) before freezing and remained visible in all these oocytes throughout the preparation for freezing up to the time that they were loaded into cryopreservation straws. Immediately after thawing, the spindle was visible in 35.7% of oocytes, but it disappeared in all of the thawed oocytes during the subsequent washing steps. However, the spindle reappeared in all surviving thawed oocytes after washing (57.4%), by 3 h of incubation at 37°C in culture medium. CONCLUSIONS: The current techniques of oocyte freezing and thawing inevitably cause meiotic spindle destruction. All spindles observed in thawed oocytes result from post‐thaw reconstruction.

Figure 3. Sequential Polscope images of a metaphase II human oocyte in which the meiotic spindle was undetectable immediately after thawing in thawing solution 1 (A) and re‐appeared after cryoprotectant removal during incubation at 37°C in culture medium (B). Immunocytochemical visualization of residual tubulin immunoreactivity associated with chromosomes of a frozen–thawed oocyte lacking the meiotic spindle (C).