Enzyme activities of the retina and vitreous body following experimental implantation of a brass splinter

Abstract

Brass splinters weighing 28 mg were implanted in the center of the vitreous of rabbit eyes. After a few days the well-known infiltration and liquefaction of the vitreous body were observed, together with retinal necrosis. Cellular and lysosomal enzymes usually found only in very low concentrations in the vitreous body increased more than a hundredfold during the inflammatory process and the increasing opacification. The enzymes assayed were lactic dehydrogenase (LDH), phosphofructose aldolase (ALD), glycerinaldehyde phosphate dehydrogenase (GAPDH), malate dehydrogenase (MDH), glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione reductase (GR), beta-N-acetylglucose aminidase (NAcGA), and cathepsin-D. The kinetics of enzyme reproduction in the vitreous suggested that the cellular enzymes of the energy producing metabolism might originate both from the invading leukocytes as well as from the degrading retina. It seems likely that the cathepsin-D occurring in the vitreous originates mainly from the retina, and the beta-N-acetylglucose aminidase mainly from the pigment epithelium. The pathologically increased enzyme activity might well permit diagnostic conclusions concerning the intensity and stage of destruction of the retina by brass poisoning.