摘要
将经过２０～２４ｈ体外成熟培养后的牛卵母细胞在含５％ＣＯ２，９５％空气，最大相对饱和湿度和温度分别为３７℃（Ｇ１），３８℃（Ｇ２）和３９℃（Ｇ３）的培养条件下进行体外受精，以观察受精温度对牛体外受精及其随后胚胎发育的影响。结果显示，不同受精温度对牛卵母细胞体外精子入卵率（９３．６％～１００％）及受精卵裂率（７８．５％～８０．３％）无明显影响；而早期胚胎卵裂发育速度、体外囊胚发育速度及体外囊胚发育率和孵化率均随着受精温度的升高呈上升趋势。在ＩＶＦ４２～４６ｈ，Ｇ３发育到５细胞以上卵裂周期阶段的早期胚胎比率（４０．３％）非常显著地高于Ｇ２（２４．３％）和Ｇ１（１８．８％，Ｐ＜０．００１）；而相应处于２细胞阶段的胚胎比率（Ｇ３为１４．６％）则十分显著地低于Ｇ２（２５．２％）和Ｇ１（３０．１％，Ｐ＜０．０１）。Ｇ３的囊胚体外孵化率（７５．８％）也非常明显地高于Ｇ２（５１．９％）和Ｇ１（４７．９％，Ｐ＜０．００）。结果表明，受精温度（３７～３９℃）主要影响早期胚胎的质量，从而影响到其随后的囊胚发育率、发育速度及其孵化率，而对卵母细胞的受精、卵裂率无明显影响。
The objectives of this experiment were to investigate the effect of temperature on the in vitro fertilization (IVF) of bovine oocytes derived from in vitro maturation (IVM) and their subsequent embryonic development. After IVM for 20￣24 h, bovine oocytes were fertilized at 37℃ (G1), 38℃ (G2) and 39℃ (G3) respectively in a humidified atmosphere of 5% CO2 in air. IVM and IVF of bovine oocytes were performed using the same methods as previously described by Tan & Lu. Cleavage rate (CR) was checked at 42 ￣46 h after insemination and 2￣8 cells stage embryos were co-cultured with glanulosa cell monolayers until their hatched stage. The result showed that the sperm penetration rate (93. 6 %￣100% ) and CR (78. 5 % ￣80. 3 % ) of the oocytes after IVF were not significantly defferent among the 3 groups; but the speed of cleavage of early stage embryo,blastocyst development and their hatched rate in vitro were increased as the fertilization temperature was raised from 37℃ to 39℃. At 42￣46 h after insemination, the rate of embryos (≥5-cell) in G3 (40. 3% ) was significantly higher than that in G2 (24. 3%) and G1 (18. 8%, P<0. 001); while the rate of 2-cell stage embryos in G3 (14. 6% ) was significantly lower than that in G2 (25. 2% ) and G1 (30. 1 %, P<0. 01). Also, the hatched rate of blastocyst in G3 (75. 8% ) was significantly higher than that in other two groups (G2,51. 9% and G1, 47. 9%, P < 0. 001 ).It is concluded that the cleavage speed of early bovine embryos and their subsequent developmental capacity were temperature dependent,but the sperm penetration and cleavage rate were not.
关键词
牛
卵母细胞
体外受精
受精
温度
bovine oocyte
in vitro fertilization
insemination temperature
nuclei development
cleavage rate
blastocyst rate
hacthed rate of blastocyst
