Hyalocyte-like cells are more numerous in the posterior chamber than they are in the vitreous of the rabbit eye.

The distribution and concentration of free cells inside the eye chambers of rabbits were investigated using semi-quantitative analysis of histological paraffin sections. Studies using light (methacrylate sections) as well as transmission and scanning electron microscopy were undertaken for the morphological characterization of the free cells. Immunocytochemistry and autoradiography were employed in an attempt to find out their nature and their origin, respectively. It was observed that cells morphologically similar to the vitreous hyalocytes were more numerous inside the posterior chamber than were the hyalocytes in the cortical vitreous. Neither the hyalocytes nor the posterior-chamber cells reacted with an antibody to rabbit macrophages. The finding of labeled free cells after an intravitreal injection of 3H-thymidine indicates that these cells can renew themselves and that their number does not depend exclusively on monocytes migrating from the blood stream to the eye chambers, as is believed to occur. In conclusion, hyalocytes or hyalocyte-like cells are more concentrated in the posterior chamber than they are in the vitreous. Both the hyalocytes and the posterior-chamber cells could not be characterized as fully developed macrophages. Copyright 1998 Academic Press.