Gametes and fertilization in the Chinese hamster
Gametes and fertilization in the Chinese hamster
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中国仓鼠的配子和受精
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
K. Mikamo
中科院分区：
文献类型：
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作者：
R. Yanagimachi;Y. Kamiguchi;S. Sugawara;K. Mikamo
每个新鲜排卵的卵都被紧凑的卵丘包围。正常卵子的总直径（包括透明带）约为100μm。卵丘细胞，特别是靠近卵子的细胞，呈红色排列在粘性非细胞基质中。精子的长度约为250微米。头部是一个巨大的顶体，可以用光学（相差）显微镜轻松检查其中的变化。当暴露于生理盐溶液时，睾丸精子要么一动不动，要么缓慢弯曲尾巴的后半部分。来自附睾头的精子高度活跃，弯曲整个尾部。他们中的一些人逐渐行动起来。来自输精管的成熟精子活动能力很强，可以直线运动或绕圈运动。它们僵硬地摇动尾巴，但并不弯曲。
在正常交配的雌性中，受精在排卵后 2 至 3 小时内开始，并在接下来的 4 至 5 小时内完成。大约受精时，在壶腹液或卵丘内游动的精子会弯曲其尾巴的前半部分（大致相当于中段区域）。这种奇特的运动可能与其他几种哺乳动物物种中报道的所谓精子“过度激活”是同源的。卵丘内活跃的精子或无透明带，顶体帽发生改变（“塌陷”）或无顶体帽。精子头通常垂直或几乎穿过透明带，但在某些情况下路径是倾斜的。在检查的最近受精卵中，有 54% 的精子尾部整个长度都位于卵周间隙内；在另外 46% 的蛋中，不同长度的尾部反映了卵黄周围空间，甚至在蛋第一次卵裂之前，尾部就从许多蛋的卵黄中挤出。
当卵丘中的未受精卵与输精管精子在改良的蒂罗德溶液（m-TALP）中受精时，大约80%的受精卵在受精后4-6小时内受精。绝大多数是单精子的。当在授精前将卵子从卵丘中释放出来时，没有一个受精，这表明卵丘细胞或其基质在所采用的体外条件下辅助精子的获能和/或顶体反应。无论授精时卵子周围是否存在卵丘，睾丸或附睾精子都不会使卵子受精。
Freshly ovulated eggs are each surrounded by a compact cumulus oophorus. The overall diameter of the normal egg (including the zona pellucida) is about 100 μm. Cumulus cells, particularly those near the egg, are arranged redially in a viscous noncellular matrix. The spermatozoon is about 250 μm in length. The head a large acrosome, changes in which can be readily examined with the light (phase- contrast) microsope. When exposed to physiological salt solutions, testicular spermatozoa either were motionless or flexed the posterior half of their tails slowly. Spermatozoa from the caput epididymis were highly motile, flexing the entire tail. A few of them moved progressively. Mature spermatozoa from the vas deferens were highly motile and moved either straightforward or in a circle. They vibrated their tails stiffly without flexing them.
In normally mated females, fertilization began sometime between 2 and 3 h after ovulation and was completed within the next 4 to 5 h. Spermatozoa swimming in the ampullary fluid or within the cumulus oophorus about the time of fertilization flexed the anterior half (which roughly corresponds to the midpieac region) of their tails. This peculiar movement may be homologous to the so-called “hyperactivation” of spermatozoa as reported in several other mammalian species. Actively motile spermatozoa within the cumulus or no the zona pellucida had either modified (“collapsed”) or no acrosomal caps. The sperm head usually passed verticually or nearly through the zona, but the path was oblique in some instances. In 54% of the recently fertilized eggs examined, the entire length of the sperm tail was within the perivitelline space; in the other 46% of the eggs varying lenghts of the tail remined the perivitelline space, the tails were extruded from the vitellus of many eggs even before the eggs began their first cleavage.
When unfertilized eggs in the cumulus oophorus were inseminated with vas deferens spermatozoa in a modified Tyrode's solution (m-TALP), about 80% of them were ferrtilized by 4–6 h after insemination. The vast majority were monospermic. When eggs were freed from the cumulus prior to insemination, none were fertilized, suggesting that the cumulus cells or their matrix assisted capacitation and/or the acrosome reaction of the spermatozoa under the in vitro conditions employed. No eggs were fertilized by the testicular or caput epididymal spermatozoa regardless of the presence or absence of cumulus oophorus around the eggs at the time of insemination.