Park K W, Iga K, Niwa K
Division of Bioresources Science, Graduate School of Natural Science and Technology Okayama University, Okayama 700, Japan.
Theriogenology. 1997 Nov;48(7):1127-35. doi: 10.1016/s0093-691x(97)00345-2.
When cumulus-enclosed bovine oocytes were cultured for 24 h in serum-free medium containing 0 to 50 ng/ml EGF, the proportions of oocytes reaching metaphase II were higher (P < 0.05) in the presence of 30 ng/ml EGF (88.1 +/- 1.3%) than under control conditions (65.5 +/- 3.5%) or in the presence of 10 ng/ml (73.9 +/- 4.5%) and 50 ng/ml (73.6 +/- 4.0%) EGF. When oocytes matured under these conditions were inseminated in vitro, the proportions of oocytes penetrated were higher (P < 0.05) in 10 to 50 ng/ml EGF (96.7 +/- 3.3 to 100%) than in its absence (77.9 +/- 8.9%). However, the proportions of penetrated oocytes with male and female pronuclei did not differ among the different groups (96.7 +/- 3.3 to 100%). When oocytes were matured under the same conditions, fertilized in vitro, and cultured until 192 h post insemination in a chemically-defined medium, the proportion of embryos at the >/=2-cell stage was higher (P < 0.05) in the groups treated with 30 ng/ml (96.1 +/- 2.5%) and 50 ng/ml (90.6 +/- 3.5%) EGF than in the controls (71.8 +/- 3.1%) at 48 h post insemination. Although there were no differences in the proportions (37.3 +/- 5.3 to 47.2 +/- 5.8%) of >/=morulae at 144 h post insemination among treatments, the proportion of embryos developing to the blastocyst stage was higher (P < 0.05) in the presence of 10 to 50 ng/ml EGF (16.5 +/- 2.0 to 20.8 +/- 4.9%) than in control medium (3.4 +/- 2.1%). The mean blastocyst cell number at 192 h post insemination did not differ between culture media in the presence (91 to 107 cells) and the absence (116 cells) of EGF (10 to 50 ng/ml) during maturation. Thus, higher proportions of oocytes matured in serum-free medium with EGF than without EGF could develop to the blastocyst stage in a chemically-defined medium after in vitro fertilization. These results indicate that EGF can induce not only nuclear maturation but also cytoplasmic maturation of cumulus-enclosed bovine oocytes in vitro.
当将卵丘包裹的牛卵母细胞在含有0至50 ng/ml表皮生长因子（EGF）的无血清培养基中培养24小时时，在存在30 ng/ml EGF（88.1±1.3%）的情况下，达到中期II的卵母细胞比例高于对照条件下（65.5±3.5%）或存在10 ng/ml（73.9±4.5%）和50 ng/ml（73.6±4.0%）EGF的情况（P<0.05）。当在这些条件下成熟的卵母细胞进行体外受精时，在10至50 ng/ml EGF存在下（96.7±3.3%至100%）卵母细胞被穿透的比例高于不存在EGF的情况（77.9±8.9%）（P<0.05）。然而，不同组中具有雄原核和雌原核的被穿透卵母细胞比例没有差异（96.7±3.3%至100%）。当卵母细胞在相同条件下成熟、体外受精并在化学限定培养基中培养至受精后192小时时，在受精后48小时，用30 ng/ml（96.1±2.5%）和50 ng/ml（90.6±3.5%）EGF处理的组中≥2细胞阶段的胚胎比例高于对照组（71.8±3.1%）（P<0.05）。尽管在受精后144小时各处理组中≥桑葚胚的比例（37.3±5.3%至47.2±5.8%）没有差异，但在10至50 ng/ml EGF存在下（16.5±2.0%至20.8±4.9%）发育至囊胚阶段的胚胎比例高于对照培养基（3.4±2.1%）（P<0.05）。在成熟过程中存在（91至107个细胞）和不存在（116个细胞）10至50 ng/ml EGF的培养基之间，受精后192小时的平均囊胚细胞数没有差异。因此，在无血清培养基中添加EGF成熟的卵母细胞比未添加EGF的卵母细胞在体外受精后在化学限定培养基中能发育至囊胚阶段的比例更高。这些结果表明，EGF不仅能诱导卵丘包裹的牛卵母细胞核成熟，还能诱导其细胞质成熟。
