Zenzes MT, Bielecki R, Casper RF, Leibo SP. Effects of chilling to 0 degrees C on the morphology of meiotic spindles in human metaphase II oocytes.
Fertil Steril 2001;
75:769-77. [PMID:
11287033 DOI:
10.1016/s0015-0282(00)01800-8]
[Citation(s) in RCA: 142] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE
To determine the effects of chilling to 0 degrees C on the meiotic spindle of human metaphase II oocytes, as observed by optical sectioning microscopy.
DESIGN
Laboratory study.
SETTING
Academic research laboratory in a medical school.
PATIENT(S)
Seventy-two women undergoing infertility treatment donated a total of 108 oocytes.
INTERVENTION(S)
Metaphase II oocytes were stripped of their cumulus cells, cooled directly to 0 degrees C, and held for periods of 1 to 10 minutes. They were then fixed at 37 degrees C, stained for immunofluorescence, and examined microscopically.
MAIN OUTCOME MEASURE(S)
Morphology of the meiotic spindle in chilled and control oocytes.
RESULT(S)
Microscopic evaluations of 46 chilled oocytes revealed various time-dependent changes in microtubules compared to 9 control oocytes. After 1 minute at 0 degrees C, spindle damage was negligible, but in oocytes cooled for 2 or 3 minutes, there was obvious shortening of the spindle and loss of polarity. Cooling to 0 degrees C for 4 to 9 minutes resulted in increasingly more drastic changes; by 10 minutes the spindles had totally disappeared. Despite depolymerization of microtubular tubulin at 0 degrees C, the chromosomes did not become dispersed, but remained anchored even in the absence of spindles.
CONCLUSION(S)
Even brief exposure of human oocytes to temperatures near 0 degrees C causes profound alterations of the meiotic spindle.
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