A STUDY OF INTERCELLULAR BRIDGES DURING SPERMATOGENESIS IN THE RAT
A STUDY OF INTERCELLULAR BRIDGES DURING SPERMATOGENESIS IN THE RAT
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DOI：
10.1002/aja.1001800102
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发表时间：
1987-09-01
影响因子：
--
通讯作者：
RUSSELL, LD
中科院分区：
文献类型：
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作者：
WEBER, JE;RUSSELL, LD
对大鼠精子发生过程中的细胞间桥进行了形态学评价。在精子发生的不同阶段，桥的尺寸和关系有所不同。精原细胞和精母细胞的细胞分裂导致预先存在的桥梁的分区称为桥梁分区复合物，这是详细描述的复杂结构，因为是新的桥梁形成的过程。减数分裂前桥的结构是一致的，但是，在精子发生，桥的结构和桥的内容进行修改，在其发展的特定阶段。与早期第1步精子细胞的细胞质方面相关的质膜密度分离成多个致密带，环绕晚期第1步精子细胞桥的外周面。在精子发生的第2步，这些致密带与几个内质网池相连，随后在第4步合并成一个完全包围桥结构的球囊。在精子发生的第10-13步，单个内质网小囊泡化为许多较小的池。此外，在桥通道内出现了有界密度（直径为10-12 nm）。在精子发生的第17步，内质网结合的密度不再明显，但内质网的闭合网络，通常在一个球体的配置，占据了整个桥的中心区域。在第19步精子细胞中，桥通道内的滑面内质网和排列在桥通道内的多个池逐渐移位。桥梁的地下密度逐渐失去了它的重要性。一些细胞质叶通过极窄的（约）连接。22 nm）细胞质通道。在胞质叶或残体的表面区域也可见到类似的通道，提示通道是桥的形成部位。就在精子细胞从细胞质叶分离或脱离之前，选择的桥似乎打开形成大的团块。精子排出后，未发现由桥连接的残留体;但从一些残留体的大小来看，怀疑它们是由一个以上的细胞质叶合并形成的。冷冻断裂表明，无论是P或E面对的质膜形成的桥梁很少膜内颗粒，这一发现表明桥结构限制跨桥膜成分的自由横向运动。总的来说，这些数据表明，桥梁不是静态的结构，但在精子发生过程中显示出大小的变化和相当大的结构相关的多样性。
A morphological evaluation of intercellular bridges was undertaken during rat spermatogenesis. The dimensions and relationships of the bridges were shown to vary during different phases of spermatogenesis. Cellular divisions of spermatogonia and spermatocytes resulted in the partitioning of pre-existing bridges by complex structures termed bridge partitioning complexes, which are described in detail, as is the process whereby new bridges are formed. The structure of premeiotic bridges was generally consistent; however, during spermiogenesis, the structure of bridges and bridge contents were modified at specific phases of their development. The plasma membrane density associated with the cytoplasmic aspect of early step 1 spermatids separated into multiple dense bands that encircled the peripheral aspect of the late step 1 spermatid bridges. By step 2 of spermiogenesis, these dense bands became associated with several cisternae of endoplasmic reticulum, which later coalesced into a single saccule that completely encircled the bridge structure by step 4. At steps 10-13 of spermiogenesis, the single saccule of endoplasmic reticulum vesiculated into many smaller cisternae. Also, filament-bounded densities (measuring 10-12 nm in diameter) appeared within the bridge channel. At step 17 of spermiogenesis, the filament-bounded densities were no longer apparent, but an anastomosing network of endoplasmic reticulum, often in the configuration of a sphere, occupied the entire central region of the bridge. In step 19 spermatids, the smooth endoplasmic reticulum within the bridge channel and the multiple cisternae lining the bridge density were gradually displaced. The subsurface density of bridges gradually lost its prominence. Some cytoplasmic lobes were connected by extremely narrow (.apprx. 22 nm) cytoplasmic channels. Similar-appearaing channels were seen on the surface zone of cytoplasmic lobes or residual bodies, this observation suggesting that channels were sites of severence of bridges. Just prior to the separation or disengagement of the spermatid from the cytoplasmic lobe, selected bridges appeared to open to form large masses. After spermiation, residual bodies were not found joined by bridges; but from the size of some of the residual bodies, it was suspected that they were formed by coalescence of more than one cytoplasmic lobe. Freeze-fracture demonstrated few intramembranous particles on either the P or E face of the plasma membrane forming the bridge; this finding suggested bridge structures restricted free lateral movement of membrane constituents across the bridge. Collectively, the data demonstrated that bridges are not static structures but show size variations and considerable structure-related diversity during spermatogenesis.