牛体外受精胚胎卵裂阶段对其体外发育能力影响的研究

Development Capacity of in vitro- Derived Bovine Embryosat Different Cleavage Stages

将经过体外成熟培养（ＩＶＭ）、体外受精（ＩＶＦ）后获得的牛早期胚胎，按其所处卵裂阶段的不同，划分为２细胞、３～４细胞和５细胞以上３个试验组，在体外条件下继续培养到发育囊胚和孵化囊胚阶段，以观察在胚胎早期，受精卵裂发育的快慢与其后胚胎所获得的继续发育能力的关系。结果显示，牛早期胚胎体外囊胚发育率的高低，与其在体外培养（ＩＶＣ）前卵裂发育的快慢成正比。在ＩＶＦ后４２～４６ｈ处于２细胞、３～４细胞和５细胞以上卵裂阶段的早期胚胎，其囊胚发育率分别为６．５％、２１．４％和４４．９％，差异非常显著（Ｐ＜０．００１）；而经过７～９ｄ的ＩＶＣ后仍滞留在ＩＶＣ前原卵裂阶段，丧失继续发育下去能力的胚胎比率则分别为５１．６％、３２．７％和２５．７％，与其ＩＶＣ前卵裂发育的快慢成反比。在ＩＶＦ后６６～７０ｈ仍处于２细胞和３～４细胞卵裂阶段的早期胚胎，其体外发育能力明显降低，囊胚发育率只有１．３％和８．２％；而滞留胚胎率则分别高达９０．９％和５９．４％。结果表明，牛体外受精早期胚胎卵裂发育的快慢，直接影响到其后体外发育的能力。

The objective of this experiment was to study the in vitro development capacity of IVM-IVF early bovine embryos at different cleavage stages.At 42- 46 or 66-70 h after IVF,the early embryos were divided into three groups according to their cleavage stages:2-cell(G1),3～4～ce (G2)and 5 (or more)-cell(G3),and co-cull-tured with granulosa monolayer in vitro to blastocyst and hatched blastocyst stages.Re-sults showed the blastocyst rates of G1,G2 and G3 were 6.5%,21.4% 44.9% respec-tivelv for embryos cultured at 42-46 h after IVF. and 1.3%,8.2%,42.8%respeetivelyfor those cultured at 66-70 h after IVF,which were both significantly defferent (P <0.01),The blockfed embryo tates wre 51.6%,32.7%,25.7%and 90.0%,59.4%,35.2%respectively.These results indicated that the cleavage speed of early IVM-IVfembryos did effect their development capacity in vitro.