Analyzing Structural and Functional Testicular Anatomy

Now, Fleck, Kenzler et al. have shown that, in mice, muscle-like cells are located within the walls of seminiferous tubules. Using CLARITY and a Leica digital light-sheet (DLS) microscope, Fleck, Kenzler et al.  imaged these smooth muscle cells in the intact tissue. A 3D reconstruction of fluorescently labeled cells and organelles from light-sheet images allows unprecedented insight into testicular anatomy. The muscle cells in the tubule walls create waves of contractions that push sperm along the fluid-filled lumen. Further experiments were then conducted on cells grown in the laboratory. These experiments revealed that a signaling molecule called ATP orchestrates this moving process by activating a cascade of molecular events that result in contractions. Fleck, Kenzler et al. then utilized intravital multiphoton calcium imaging with a Leica multiphoton system to demonstrate that this mechanism occurs in living mice. Together, these results provide a better understanding of how sperm mature, which could potentially be relevant for both male infertility and birth control.