Three-dimensional structure of two different lymphatic spaces in rat testis, and the route of flow fluxes of their lymphatic fluids.

In addition to the collecting vessels, two initial lymphatic spaces were observed with light and electron microscopes. In the deep parenchyma, the peritubular lymphatic spaces surrounding the tubules were observed as polygonal piles after a corrosion casting to the testis. They were joined to the adjacent piles through fenestrae to form a loose spongiform structure. In the superficial parenchyma, the peritubular lymphatic spaces communicated to the subtunical lymphatic space on one side. The subtunical lymphatic spaces anastomosed to each other through small bypasses to form a rich network. Near the mediastinum, the peritubular lymphatic spaces bifurcated and narrowed on another side. Microradiography demonstrated two fluxes of the intratesticular lymphatic fluids; fast and slow flows. The fast flow was observed as a shaded line running into the subtunical lymphatic spaces immediately after injection of the contrast media. It remained 1 or 2 minutes and then disappeared. In contrast, the slow flux was observed as a spongiform shade shifting from the anteroposterial quadrant to the posterosuperior portion of the testis. Seven to 15 minutes were needed for the contrast media to reach near the mediastinum. Both lymphatic spaces are functionally discussed with relation to the two different fluxes of the lymphatic fluids.