Phagocytosis of polystyrene spheres in the rabbit corneal endothelium: contribution of lysosomal enzymes to the endothelial degeneration.

The rabbit corneal endothelium phagocytized polystyrene spheres 0.5 micron in diameter. After phagocytizing spheres, the endothelium degenerated, and lost from the Descemet's membrane. Lysosomal enzyme activities of the endothelium-Descemet's membrane complex, such as acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase, were assayed and the total activities per microgram DNA were almost constant. The unsedimentable activities in the complex, however, increased by phagocytosis of polystyrene spheres, which indicated an extralysosomal release of lysosomal enzymes. Released lysosomal enzymes probably would have accounted for the degeneration of the corneal endothelium.