National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics, Breeding and Reproduction, Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing, China.
Laboratory Animal Center, Peking University, Beijing, China.
Lasers Med Sci. 2019 Jul;34(5):939-945. doi: 10.1007/s10103-018-2681-8. Epub 2018 Dec 13.
Embryo vitrification has advantages in assisted reproduction yet it also induces zona hardening. Laser zona thinning (LZT) is considered as a solution yet its efficacy and security have not been well studied. In this study, we used vitrified-warmed morulae from 2-month-old and 10-month-old ICR female mice as model to investigate the impacts that LZT treatment brings to the in vitro hatching process and implantation by analyzing hatching rate, implantation rate, and blastocyst quality. The results showed that the fully hatched rate was significantly higher after LZT treatment for both young (25.7% vs. 16.2%, P < 0.05) and aged (36.6% vs. 13.2%, P < 0.01) mice. For zona-thinned morulae in young mice, its onset of hatching occurred earlier (28.6% vs. 8.8%, P < 0.01) at D4 and with a greater percentage of U-shaped hatching at D5 (48.3% vs. 33.0%, P < 0.05). LZT treatment did not induce expression change of apoptosis-related genes in all groups (P > 0.05), but for young mice, the total cell number of day 5 blastocyst in zona-thinned group was significantly less than that of the control group (40.6 ± 5.1 vs. 59.9 ± 14.5, P < 0.01). At last, there was an increasing implantation rate in zona-thinned compared to the control group for young (63.8% vs. 52.5%, P > 0.05) and aged (55.6% vs. 47.2%; P > 0.05) mice after embryos were bilaterally transferred in the same recipient. In conclusion, the significant increase of fully hatched rate after LZT treatment is related to the advanced onset of hatching as well as the enhancement of superior hatching structure, and LZT also lead to a better implantation after embryo transfer.
胚胎玻璃化冷冻具有辅助生殖的优势，但也会导致透明带变硬。激光透明带变薄（LZT）被认为是一种解决方案，但它的效果和安全性尚未得到充分研究。在这项研究中，我们使用来自 2 个月大和 10 个月大的 ICR 雌性小鼠的玻璃化-解冻桑椹胚作为模型，通过分析孵化率、着床率和囊胚质量来研究 LZT 处理对体外孵化过程和着床的影响。结果表明，LZT 处理后，年轻（25.7%比 16.2%，P<0.05）和年老（36.6%比 13.2%，P<0.01）小鼠的完全孵化率均显著提高。对于年轻小鼠的变薄透明带桑椹胚，其孵化开始时间更早（28.6%比 8.8%，P<0.01），在 D5 时 U 型孵化的比例更大（48.3%比 33.0%，P<0.05）。LZT 处理没有诱导各组凋亡相关基因表达的变化（P>0.05），但对于年轻小鼠，变薄组第 5 天囊胚的总细胞数明显少于对照组（40.6±5.1 比 59.9±14.5，P<0.01）。最后，与对照组相比，年轻（63.8%比 52.5%，P>0.05）和年老（55.6%比 47.2%；P>0.05）小鼠的双侧胚胎移植后，变薄组的着床率增加。总之，LZT 处理后完全孵化率的显著提高与孵化开始时间的提前以及更优的孵化结构增强有关，LZT 还导致胚胎移植后的着床效果更好。
