Rat kidney lysosomal membrane damage induced by suramin in vitro and in vivo

The effect of suramin, an acid naphthylamine, on rat kidney lysosomal membrane integrity was studied. Lysosomal particles were incubated with suramin (0.1-0.4 mM) and light scattering behaviour of the mixtures were subsequently measured. There was a significant decrease (P less than 0.005) in the amount of light absorbed in the presence of suramin compared to lysosomal particle suspension alone. This was accompanied by release of acid phosphatase, a lysosomal 'marker' enzyme, into the suspending medium. These effects were reduced in the presence of acetylsalicylic acid, a known lysosomal membrane stabilizer. Administration of suramin to rats resulted in loss of kidney acid phosphatase and lysozyme activities from the tissue. These results indicate labilization of rat kidney lysosomal membrane by suramin molecules both in vitro and in vivo.