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Intracytoplasmic lumina in human oviduct epithelium
H Hagiwara1, N Ohwada, T Fujimoto
1Department of Anatomy, Gunma University School of Medicine, Maebashi, Gunma, Japan.
Insights
Intracytoplasmic lumina (ICL) were identified in human oviduct epithelium using transmission electron microscopy. These structures form through the fusion of secretory granules and tubular vesicles within basally located epithelial cells.
Area of Science:
- Reproductive Biology
- Cell Biology
- Histology
Background:
- Human oviduct epithelium plays a crucial role in reproductive processes.
- The presence and function of intracytoplasmic lumina (ICL) within this epithelium are not fully understood.
- Investigating epithelial cell structures provides insights into oviduct physiology.
Purpose of the Study:
- To investigate the ultrastructure and formation of intracytoplasmic lumina (ICL) in human oviduct epithelium.
- To characterize the cellular origin and developmental stages of ICL.
- To elucidate the relationship between ICL and secretory activity.
Main Methods:
- Transmission electron microscopy (TEM) was employed to examine human oviduct epithelial tissue.
- Periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining was used to visualize specific cellular components.
- Ultrastructural analysis focused on identifying microvilli, luminal contents, and cytoplasmic vesicles.
Main Results:
- Intracytoplasmic lumina (ICL) were observed in 43 out of 60 cases.
- ICL were characterized by microvilli, granular material, and surrounding secretory vesicles.
- ICL formation involved the aggregation and fusion of secretory granules with tubular vesicles in basally located cells.
Conclusions:
- Intracytoplasmic lumina (ICL) are a distinct ultrastructural feature of human oviduct epithelium.
- ICL originate from secretory processes within basally located epithelial cells.
- The formation and potential function of ICL warrant further investigation in reproductive contexts.
Abstract:
Intracytoplasmic lumina (ICL) in human oviduct epithelium were investigated with transmission electron microscopy. ICL were found in 43 out of 60 cases examined. They were ultrastructurally characterized by microvilli lining the lumina, periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining-positive finely granular material in the lumina, and secretory vesicles in the cytoplasm surrounding the lumina. Although ICL were observed at various heights within the epithelium, they were mainly seen in basally located cells that did not face the oviduct lumen. Various stages of formation and development of ICL were observed in the basally located epithelial cells with secretory activities. Primary ICL were originated in the cytoplasm where the secretory granules were aggregated with smooth-surfaced tubular vesicles. Electron microscopic observations after PA-TCH-SP staining revealed that ICL were formed by fusion of the secretory granules with the tubular vesicles. ICL were enlarged into round profiles by further fusion of secretory granules and tubular vesicles, and subsequently opened to the oviduct lumen, or fused to each other to develop into large extracellular cysts within the epithelium.