Ultrastructural Demonstration of Transretinal Migration by Vitreal Macrophages Marked with Latex Particles

Abstract

The injection of 1.1-μm latex particles into the rabbit vitreous elicits an intravitral invasion of macrophages. The particle-filled macrophages are initially restricted to the vitreous, are later found at the vitreoretinal interface, and by 6 weeks are distributed throughout the inner layers of the retina. The phagocytes appear to lyse in the outer retinal layers, and the released particles are found between and within the cells of the photoreceptor region. The observations indicate that latex-marked macrophages from the vitreous can penetrate and migrate within the retina.

Müller glia phagocytose dead photoreceptor cells in a mouse model of retinal degenerative disease

“…6C a-e, for low magnification and Fig. 6Ca'- (17,18). Müller glia are also capable of phagocytosing biologic materials, such as melanin granules and erythrocytes, injected into the vitreous or subretinal space (47,48).…”

“…Nevertheless, the use of foreign substances may confound our understanding of the in vivo clearance of cellular debris. Unlike biologically relevant phagocytotic clearance, phagocytosed melanin granules and other foreign substances are not degraded and instead reside in Müller glia for an extended period (14,15,17,18). Cultured Müller glial cells of gold fish retina are capable of phagocytosing latex beads ex vivo; however, those Müller glia are incapable of phagocytosing those materials in vivo (49).…”

“…Despite technical limitations, the potential phagocytic activity of Müller glia has been demonstrated during the past 80 yr. After subretinal or intravitreal injection of foreign materials, those materials were subsequently observed within Müller glial cells (14)(15)(16)(17)(18)(19). Such studies indicated that Müller glia is capable of engulfing exogenous materials; nevertheless, those results did not provide insights into the in situ clearance of damaged retinal neurons.…”

Müller glial cells of the goldfish retina are phagocytic in vitro but not in vivo

“…The biological significance of phagocytosis by Miiller glia in the normal retina is questionable. Transportation of phagocytosed particles through the layers of the retina and release of the beads into the subretinal space is an inefficient way to remove particles from the posterior chamber of the eye, although this pathway has been described in rabbit retina (Burke and Foster, 1982). These authors observed transretinal migration E.C.…”