牦牛卵泡细胞及其卵母细胞不同发育时期的结构变化

采集成年母牦牛卵巢,通过光镜和电镜对牦牛卵泡及其卵母细胞不同发育时期的结构变化进行了观察。结果发现当卵母细胞被单层立方卵泡细胞包围时,微绒毛开始出现,而皮质颗粒、透明带则在包被2-4层卵泡细胞时开始出现。随着卵母细胞的继续发育,透明带增厚,微绒毛由粗短变为细长,密度增加;皮质颗粒、线粒体、滑面内质网等细胞器的数目不断增加,并逐渐移行到质膜下;在移行的过程中,皮质颗粒成团存在。在囊状卵泡中,卵母细胞皮质颗粒呈线形分布于质膜下,线粒体、滑面内质网又移向胞质中央。卵母细胞借助微绒毛穿过透明带与卵泡细胞胞质突起相联系。结果证明牦牛卵泡和卵母细胞不同发育时期的结构变化与其它哺乳动物的基本相似。

Structural changes of the follicular cells and oocytes during developmental stages of the yak Bos grunniens

The present study investigated the structural modulation of the follicular cells and oocytes during development of the follicle in yaks by light and electron microscopy, The results showed that cortical granules and zona pellucida appeared when oocytes were encircled by 2-4 layers of cuboidal follicular cells. A few short microvilli began to emerge on the oolemma when they were surrounded by simple cuboidal follicular cells. With the development of oocytes, microvilli became long and the zona pellucida became thicker. The number of mitochondria, smooth endoplasmic reticulum and cortical granules all increased and they moved to the cortical region gradually. In oocytes of tertiary follicles, cortical granules began to arrange themselves beneath the oolemma, and mitochondria dispersed toward the central region of cytoplasm. Oocyte and follicular cells were linked by zone pellucida and microvilli. The structural modulation of the follicular cells and oocytes during the development of the follicle in yaks is similar with other mammalians.