Collective cell dynamics and luminal fluid flow in the epididymis: A mechanobiological perspective

Abstract

Background: The mammalian epididymis is a specialized duct system that serves a critical role in sperm maturation and storage. Its distinctive, highly coiled tissue morphology provides a unique opportunity to investigate the link between form and function in reproductive biology. Although recent genetic studies have identified key genes and signaling pathways involved in the development and physiological functions of the epididymis, there has been limited discussion about the underlying dynamic and mechanical processes that govern these phenomena.

Aims: In this review, we aim to address this gap by examining two key aspects of the epididymis across its developmental and physiological phases.

Results and discussion: First, we discuss how the complex morphology of the Wolffian/epididymal duct emerges through collective cell dynamics, including duct elongation, cell proliferation, and arrangement during embryonic development. Second, we highlight dynamic aspects of luminal fluid flow in the epididymis, essential for regulating the microenvironment for sperm maturation and motility, and discuss how this phenomenon emerges and interplays with epididymal epithelial cells.

Conclusion: This review not only aims to summarize current knowledge but also to provide a starting point for further exploration of mechanobiological aspects related to the cellular and extracellular fluid dynamics in the epididymis.

Keywords: Wolffian duct; collective cell dynamics; epididymis; luminal fluid flow; mechanobiology.

FIGURE 1

Morphogenetic events in the murine Wolffian duct. (A) Developmental process of murine Wolffian duct, depicted in yellow, from E15.5 to E18.5. Scale bar, 200 μm. The images were reproduced with slight modifications from a previous publication under the CC BY 3.0 license. (B) Time-lapse snapshots of epithelial cells in a developing murine Wolffian duct. The two daughter cells resulting from cell division are denoted by yellow asterisks, with one of the daughter cells highlighted in green. A group of cells, including the green cell and four adjacent cells, colored in magenta and light blue undergo cell intercalation. Scale bar, 10 μm. The images were reproduced from a previous publication under the CC BY 4.0 license. (C) A three-dimensional view of the duct, where the arrowhead indicates a perversion, where the helical handedness of the duct changes. Scale bar, 100 μm. The image was reproduced from a previous publication under the CC BY 3.0 license.

FIGURE 2

Structure of the adult murine epididymis. (A) Stereomicroscope image of the epididymis and testis. Scale bar, 1 mm. (B) Fluorescence image of the epididymal duct in the proximal region of epididymis. The boundary between caput and corpus is represented by the orange dotted line. Scale bar, 1 mm.

FIGURE 3

Section images of the murine epididymis. Paraffin slices stained with hematoxylin and eosin in the initial segment (A) and the cauda (B). No spermatozoa can be observed in the lumen in the initial segment in contrast to the cauda. Scale bars, 100 μm. L, lumen of the duct.