Okitsu O, Yamano S, Aono T
Department of Obstetrics and Gynaecology, University of Tokushima School of Medicine, Japan.
Zygote. 2001 Feb;9(1):89-95. doi: 10.1017/s0967199401001095.
The aim of this study was to investigate whether bovine spermatozoa possess so-called sperm factor in the cytosolic fraction (CF) which activates bovine oocytes, and whether bovine oocytes matured in vitro are activated by microinjection of CF extracted from spermatozoa of other species. In the first experiment, bovine and human spermatozoa were microinjected into ooplasm of bovine oocytes matured in vitro. Secondly, CF from bovine and human spermatozoa were injected into bovine oocytes. In the third, CF from human spermatozoa was injected into human unfertilised oocytes obtained 18-20 h after clinical intracytoplasmic sperm injection (ICSI). We found that microinjection of bovine spermatozoa into bovine oocytes induced oocyte activation, as shown by resumption of meiosis and formation of a female pronucleus, at a significantly higher rate than the bovine sham injection (63.0% vs 43.0%; p < 0.05). On the other hand, there was no significant difference in activation rate between the human sperm injection (35.9%) and the human sham injection (22.9%). Furthermore, microinjection of bovine sperm CF into bovine oocytes induced oocyte activation at a significantly higher rate than the human CF injection or sham injection (75.9% vs 14.8%, 20.4%; p < 0.01). Formation of a single female pronucleus and second polar body extrusion was observed in 95.1% of activated oocytes after bovine sperm CF injection. When human sperm CF was injected into human unfertilised oocytes, the activation rate was significantly higher than following sham injection (76.9% vs 44.0%; p < 0.05). These results indicate the presence of sperm factor in bovine sperm CF which activate bovine oocytes, and suggest the possibility that sperm factor has species-specificity at least between bovine and human.
本研究的目的是调查牛精子的胞质部分（CF）中是否存在可激活牛卵母细胞的所谓精子因子，以及体外成熟的牛卵母细胞是否会被注射从其他物种精子中提取的CF所激活。在第一个实验中，将牛精子和人精子显微注射到体外成熟的牛卵母细胞的卵质中。其次，将来自牛精子和人精子的CF注射到牛卵母细胞中。在第三个实验中，将来自人精子的CF注射到临床卵胞浆内单精子注射（ICSI）后18 - 20小时获得的人未受精卵母细胞中。我们发现，将牛精子显微注射到牛卵母细胞中可诱导卵母细胞激活，表现为减数分裂恢复和雌原核形成，其发生率显著高于假注射组（63.0%对43.0%；p < 0.05）。另一方面，人精子注射组（35.9%）和人假注射组（22.9%）之间的激活率没有显著差异。此外，将牛精子CF显微注射到牛卵母细胞中诱导卵母细胞激活的发生率显著高于人CF注射组或假注射组（75.9%对14.8%，20.4%；p < 0.01）。在注射牛精子CF后，95.1%的激活卵母细胞中观察到单个雌原核形成和第二极体排出。当将人精子CF注射到人的未受精卵母细胞中时，激活率显著高于假注射组（76.9%对44.0%；p < 0.05）。这些结果表明牛精子CF中存在可激活牛卵母细胞的精子因子，并提示精子因子至少在牛和人之间具有物种特异性的可能性。
