Role of oxygen radicals in phorbol myristate acetate-induced glomerular injury.

Phorbol myristate acetate (PMA) is known to be a potent activator of neutrophils and macrophages resulting in the generation of large amounts of oxygen-free radicals by these cells. When injected into the left renal artery of 250 to 300 g male Sprague-Dawley rats, PMA caused significant proteinuria compared to control rats which received normal saline (35.4 +/- 4 mg/24 hr in PMA treated vs. 14.1 +/- 0.9 mg/24 hr in saline control, P less than 0.02). The proteinuria was associated with evidence of glomerular injury. These PMA-induced alterations were not prevented by complement depletion but were prevented by prior depletion of neutrophils. The coinstillation of catalase prevented the development of the proteinuria (catalase + PMA 12.7 +/- 2.3 mg/24 hr vs. PMA alone 38.2 +/- 5.7 mg/24 hr, P less than 0.001) suggesting that H2O2 and/or its metabolites derived from neutrophils were important in the PMA-induced proteinuria. In contrast, superoxide dismutase (SOD) had no effect. We conclude that, following the intra-arterial injection of PMA, neutrophil-derived hydrogen peroxide and/or its metabolic products are capable of causing acute proteinuria in association with morphological alterations in glomeruli of rats.