ABSTRACT
Objective Based on the techniques of continual tissue slices, the human epididymis was rebuilt for understanding the anatomical and histological features of the epididymal ducts. Methods Continuous tissue slices of one human epididymis were performed and digital slice images were obtained through scanning with Leica-Aperio AT2; the pipe wall of epididymal duct was aligned in sequence with Photoshop CC 2018 software and VGStudio MAX V3.0 software was used for three-dimensional synthesis. Finally, the later modification was carried out with Materialise Magics V22.0 software. Another human epididymis was used for electron microscopy. The histological features of epididymal ducts were analysed by combining slices and three-dimensional reconstruction. Results A total of 4331 and 543 slices in transverse and sagittal section respectively were prepared with a thickness of 7 |ira. According to the three-dimensional structure, regional distribution of human epididymal duct could be found obviously and the caput, corpus and cauda of epididymis could be clearly divided into 7, 9 and 4 subregions respectively. There were tissue intervals among adjacent subregions and epididymal ducts were disordered within each subregion, but differences were existed in tubular diameter and epithelial structure, and adjacent subregions were connected by single epididymal duct in the corpus and cauda. Conclusion The human epididymal duct can be successfully reconstructed by continual tissue slices technique. The human epididymal duct has regional distribution in space obviously and there are differences between different subregions.
ABSTRACT
The two-dimensional model of cell culture is an important method in the study of testicular development and spermatogenesis but can not effectively mimic and regulate the testicular microenvironment and the whole process of spermatogenesis due to the lack of relevant cell factors and the disruption of a three-dimensional spatial structure. In the past 20 years, the development and optimization of the in vitro model such as testis organotypic culture and in vivo model such as testis transplantation achieved a transformation from two- to three-dimension. The maintenance and optimization of the testicular niche structure could mimic the testicular microenvironment and cell types including Leydig, Sertoli and germ cells, which showed similar biological behaviors to those in vivo. Besides, the cell suspension or tissue fragment floats in the gas-liquid interface so that the development of somatic and germ cells is well maintained in vitro whilst the feedback linkage between grafted testis tissue and hypothalamus-pituitary of the host rebuilt in the in vitro model provides an endocrinological basis for spermatogenesis, which serves as an effective methodology to better understand the organogenesis and development of the testis as well as testicular function regulation, advancing the concept of treatment of male infertility. Al- though each of the methods may have its limitations, the progress in the processing, freezing, thawing, and transplantation of cells and tissues will surely promote their clinical application and present their value in translational medicine.