Inhibition of lysosomal degradation in retinal pigment epithelium cells induces exocytosis of phagocytic residual material at the basolateral plasma membrane.

PURPOSE

To analyze chloroquine-induced morphological changes in the retinal pigment epithelium (RPE) and Bruch's membrane (BM).

METHODS

Retina-choroid complexes of chloroquine-treated Long-Evans rats were analyzed by electron microscopy.

RESULTS

Intercellular spaces between the RPE cells and BM were enlarged. Residual material from phagosomes was released into these enlarged spaces. Debris accumulated within BM and encircled choriocapillaris endothelial cells.

CONCLUSION

There is a release of undegraded phagocytic material (rod outer segments) into the extracellular space between BM and RPE cells, following inhibition of lysosomal degradation. Electron-dense deposits in BM and choriocapillaris may lead to reduced oxygen and nutrition flow.