猪卵泡形成中后期卵母细胞发育和闭锁变化的超微结构研究

本文采用了电镜观察猪卵泡形成中后期卵母细胞(OC)的超微结构,其结果有两种变化:一是进行性变化,其核在排出第一极体以前,都处于生发泡阶段。细胞质内含大量脂滴(Li),线粒体(Mi)和内质网(ER)囊泡集群分布于近皮质区;随OC 的增大,皮质颗粒(CGs)的直径、分布密度都增加,但膜距减少。微绒毛(MV)数量、直径和长度逐渐变少、变粗、变短,极少见到高尔基复合体(Go)。颗粒细胞(GC)逐渐老化。二是闭锁变化,其核膜皱折,染色质浓缩,Mi 互相融合并出现空泡。ER 囊扩大融合,Li 减少,核蛋白体和糖元颗粒不清,卵膜皱缩,与透明带间出现大的裂隙。GC 质中出现空泡,核膜破裂。GC 数量减少,严重的完全消失。统计分析表明,卵泡直径5mm 时其闭锁率最高。

ULTRASTRUCTURAL STUDIES ON THE DEVELOPME NTAL AND ATRETIC CHANGES OF OOCYTES IN MIDDLE AND LATE FOLLICLES OF SOWS

There were two kinds of changes in the ultrastructure on the developmen-tal and atretic changes of oocytes in middle and late follicles of sows.Thefirst was a progressive change.Before the exclusion of the first polar body,the nuclei of the oocytes were all at the germinal vesicle stage.There were a lotof lipid drops in the cytoplasm.The mitochondria and endoplasmic reticulumclustered near the cortical region and they tended to disperse throughout thecytoplasm in the oocytes of bigger follicles.As the oocytes grew,corticalgranules increased in diameter and in dispersing density,but their distanceto the oolemma was shortened.The microvilli of the oocytes gradually reducedin number,thickened in diameter and shortened in length.The Golgi complexwas seldom visible.Granular cells aged gradually,their projections wereconnected to the oolemma through desmosomes.The second,was an atreticchange.The nuclear envelope wrinkled,the chromatin condensated and themitochondria fused with each other,and some vacuoles appeared in them.Endoplasmic reticulum (?)vesicles enlarged and fused with one another.Lipiddrops were reduced in number.Ribosome and glycogen granules could not beseen clearly.The oolemma had wrinkled so much that some large crevicesappeared between the zona peliucida and the oolemma.Some vacuoles appearedin the cytoplasm of the granular cells.Their nuclear envelope had broken.Granular cells decreased in number.In some extreme cases they were totallyabsent.Statistical analysis showed that the rate of follicular atresia was thehighest when the follicular diameter was 5mm in length.