Department of Biology, Virginia Wesleyan College, Norfolk, VA 23502-5599, USA.
Theriogenology. 2010 Jul 15;74(2):165-72. doi: 10.1016/j.theriogenology.2010.02.003. Epub 2010 May 8.
A meta-analysis of cryopreservation studies vitrifying mouse embryos was undertaken to determine the treatment effect of vitrification. Treatment by vitrification decreased embryo viability compared with controls: the odds ratio was 9.02 (CI: 3.73-21.78; P < 0.001), a 24.90% (CI: 14.88-34.91; P < 0.001) reduction in risk was associated with embryos in the control group, and for every 4.00 (CI: 3.91-4.09) embryos treated by vitrification, one does not survive. A multiple regression analysis evaluated covariates of embryo survival. For each hour increase post-hCG treatment when embryos were cryopreserved, there was a decrease of 0.36% (SEM +/- 0.01) in survival (P < 0.001). The number of embryos surviving vitrification decreased 0.25% (SEM +/- 0.02) per day increase in age of the female mouse (P < 0.001), whereas there was no significant difference for control group embryos. For each 1 h increase post-hCG treatment after cryopreservation when blastocysts were assessed for viability, there was a decrease of 0.13% (SEM +/- 0.01) in survival. The later interval post-hCG treatment when blastocysts were assessed, the less viable they were compared with earlier blastocysts, independent of the vitrification protocol. This effect was not observed for control embryos. A high percentage of variability in the treatment effect for vitrification was likely due to underlying heterogeneity among studies. A portion of the risk associated with vitrification could be attributed to the general effects of cryopreservation. Future research should identify effects in a cryopreservation protocol specific to vitrification that affect viability of mouse embryos.
对玻璃化冷冻保存小鼠胚胎的研究进行了荟萃分析，以确定玻璃化的处理效果。与对照组相比，玻璃化处理降低了胚胎的存活率：优势比为 9.02（CI：3.73-21.78；P<0.001），对照组中胚胎的风险降低了 24.90%（CI：14.88-34.91；P<0.001），每处理 4.00 个（CI：3.91-4.09）胚胎，就有一个胚胎不能存活。多元回归分析评估了胚胎存活的协变量。在 hCG 处理后冷冻保存的胚胎每增加 1 小时，存活率就会降低 0.36%（SEM +/- 0.01）（P<0.001）。雌性小鼠年龄每增加 1 天，玻璃化冷冻保存的胚胎存活率就会降低 0.25%（SEM +/- 0.02）（P<0.001），而对照组胚胎则没有显著差异。在 hCG 处理后冷冻保存的胚胎评估其活力时，每增加 1 小时，存活率就会降低 0.13%（SEM +/- 0.01）。胚胎评估的 hCG 处理后时间间隔越晚，与早期胚胎相比，其活力越低，与玻璃化方案无关。这一效应在对照组胚胎中并未观察到。玻璃化处理效果的变异性很大，可能是由于研究之间存在潜在的异质性。玻璃化处理所带来的部分风险可能归因于冷冻保存的一般影响。未来的研究应该确定特定于玻璃化的冷冻保存方案中影响小鼠胚胎活力的因素。
