The phagocytic activity of the trabecularmeshwork endothelium. An electron-microscopic study of the vervet (Cercopithecus aethiops).

In living vervets, the cells bordering the anterior chamber of the eye were allowed contact for various periods of times (1–40 min) with India ink-, gold- or mercurysulfide particles before fixation. In electronmicrographs the trabecular endothelium cells showed an intense microphagocytic activity, particles were engulfed already after 2–5 min. Various types of free cells (histiocytes, wandering cells etc.) were also found within the trabecular meshwork involved in the process of microphagocytosis. These cells probably originate in the iris tissue or emigrate from the ciliary body. Having engulfed the foreign material in vacuoles of various sizes bordered by a fine membrane, the trabecular endothelial cells change their form and appearance. They often detach tehmselves from the trabecular lamellae and leave the meshwork by way of Schlemm's canal. Cells were found which penetrated with muschroom-like processes through small intercellular stomata in the inner wall of Schlemm's canal (Figs. 18, 19). The trabecular cells are also able to engulf red blood cells or bacteria entirely (Figs. 10, 14). The microphagocytic activity of the inner wall endothelium of Schlemm's canal is low. Sometimes little vacuoles filled with the particles were seen. However in contrast to the trabecular cells no form changes occur within the inner wall endothelium. The particles seem to pass through the cells while the cells remain extended in the row lining the canal (cytopempsis).