On the problem of the phagocytic capacity of Sertoli cells. Electron microscopic study in the rat

To study the real phagocytic capacity of Sertoli cells the following experiments were carried out: carbon colloidal solution or thorium dioxide of particle size 0.01--0.03 micrometer as 2% solution were injected in rat testes at a speed of 50 microliter per minute by means of a infusion pump. The site of injection was made either in the intertubular species under the albuginea or in the lumen of seminiferous tubules using glass 120 micrometer-gauge needles connected to the pump syringe. 30 to 240 minutes after the injection the tissues were fixed by perfusion of 2% glutaraldehyde and embedded for EM. It was observed: 1) particles injected into the intertubular species were not able to pass through the tubular wall and were either trapped by the connective tissue macrophages or drained by the lymphatic vessels; 2) intraluminal particles were not phagocyted by the Sertoli cells and remained in the lumen. The behavior of the Sertoli cells did not match that of phagocytes since they did not show their devouring capacity for the inert particles. These results are consistent with the interpretation that the current disposal of either debris by Sertoli cells depends on autophagic dissolution rather than n macrophagic capacity.