牛体外受精胚抗冻性原因初探

The Preliminary Research on Freezing Viabilities of Bovine in vitro Fertilized Embryos

采用M 199、SOFaa(aa :aminoacids)和SOF对牛体外受精卵进行发育培养 ,比较了这 3种条件下培养出来的囊胚冷冻存活率 ,并采用脂肪颗粒染色法初步分析了影响胚胎抗冻性的原因。 3个处理组的冷冻存活率分别为78.5 %、46 .4%和 17.3%,三者间存在极显著差异 (P <0 .0 1)。孵化率分别为 41.9%、2 3.2 %和 0 ,三者间存在显著差异 (P <0 .0 5 )。 7枚经M199培养的囊胚均呈现均匀的小脂肪颗粒 (直径 2 .5 μm左右 ) ,SOFaa培养的 11枚胚胎中有 1枚呈不均匀的大脂肪颗粒 (直径 6 .3μm左右 ) ,其它 10枚呈均匀的小脂肪颗粒 ,而SOF组则有 84.6 %(11/13)的胚胎呈大脂肪颗粒。由此可见 ,3个处理组的胚胎冷冻存活率与小脂滴胚比率相一致。这一结果表明 ,脂滴大小与胚胎抗冻能力具有一定的相关性 ,小脂滴胚较大脂滴胚具有更强的抗冻能力 ;发育培养过程中使用不同的培养液以及氨基酸的添加能影响胚胎内脂滴的大小 ,从而影响胚胎的抗冻能力。

Bovine IVF embryos were cultured in M199, SOF+amino acids (SOFaa) and SOF respectively, the freezing viabilities of blastocysts derived from the three culture conditions were compared, and the reason resulted in different freezing viabilities was also investigated by lipid droplet staining. The survival rates of blastocysts derived from M199, SOFaa and SOF after freezing-thawing were 78.5%, 46.4% and 17.3%, and the hatching rates were 41.9%, 23.2% and 0, respectively. There were significant differences among them (P<0.01). All of 7 blastocysts cultured in M199 appeared homogeneous small lipid droplets(diameter: about 2.5μm); Among 11 blastocysts cultured in SOFaa, one presented heterogenous large lipid droplets(diameter: about 6.3μm), and the other 10 blastocysts appeared small lipid droplets. The percentage of embryo with small lipid droplets from M199, SOFaa and SOF were coincident with the freezing-thawing results of these three kinds of embryos which suggested that there was a relationship between lipid droplet size and freezing viability of embryo. The freezing viability of blastocyst with small lipid droplets was higher than that of blastocyst with large lipid droplets. Different media and amino acids used for in vitro development culture of bovine IVF oocytes affected the freezing viabilities of blastocyst by affecting the lipid droplet size.