In Vivo Dynamic Volumetric Imaging of Mouse Testis and Epididymis With Optical Coherence Tomography†

Authors

Kohei Umezu
Guzel R Musina
Irina V Larina

Publication Date

2-10-2024

Journal

Biology of Reproduction

DOI

10.1093/biolre/ioad158

PMID

37971359

PMCID

PMC10873499

PubMedCentral® Posted Date

11-16-2023

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Mice, Animals, Male, Epididymis, Testis, Tomography, Optical Coherence, Semen, Spermatozoa, epididymis, in vivo imaging, intravital microscopy, optical coherence tomography, sperm transport, testis

Abstract

The implementation of live imaging in reproductive research is crucial for studying the physiological dynamics. Sperm transport is a highly dynamic process regulated by tubular contractions and luminal flows within the male reproductive tract. However, due to the lack of imaging techniques to capture these dynamics in vivo, there is little information on the physiological and biomechanical regulation of sperm transport through the male reproductive tract. Here, we present a functional in vivo imaging approach using optical coherence tomography, enabling live, label-free, depth-resolved, three-dimensional, high-resolution visualization of the mouse testis and epididymis. With this approach, we spatiotemporally captured tubular contractility in mouse testis and epididymis, as well as microstructures of these reproductive organs. Our findings demonstrated that the contraction frequency varies significantly depending on the epididymal regions, suggesting the spatial regulation of epididymal contractility. Furthermore, we implemented quantitative measurements of the contraction wave and luminal transport through the epididymal duct, revealing the physiological dynamics within the male reproductive tract. The results show that the contraction wave propagates along the epididymal duct and the wave propagation velocity was estimated in vivo. In conclusion, this is the first study to develop in vivo dynamic volumetric imaging of the male reproductive tract, which allows for quantitative analysis of the dynamics associated with sperm transport. This study sets a platform for various studies investigating normal and abnormal male reproductive physiology as well as the pharmacological and environmental effects on reproductive functions in mouse models, ultimately contributing to a comprehensive understanding of male reproductive disorders.

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