Presence of inflammatory cells associated with exaggerated arachidonic acid metabolism in renal injury.

Unilateral ureter obstruction induces an exaggerated prostaglandin release from isolated perfused rabbit kidneys in response to vasoactive peptides. Perfused hydronephrotic kidneys also exhibit the release of thromboxane A2 which is not detected with normal or contralateral kidneys. Reversal of the ureteral obstruction causes a decreased production of PGs and TxA2 in response to bradykinin. Morphological examination of the HNK demonstrates an enlarged interstitial space containing a fibroblast-like cell and the presence of mononuclear cells. Administration of endotoxin to the perfused HNK elicits the release of PGE2 and TxB2 consistent with the ability of endotoxin to stimulate arachidonic acid metabolism in cultured macrophage. Rabbit CLK and the cat HNK, which are deficient in macrophages, exhibit minimal PGE2 and no detectable TxA2 release after endotoxin stimulation. Cells cultured from the rabbit HNK cortex contain fibroblast-like cells and phagocytic cells which respond to BK with a profound PG production. Conditioned media from mononuclear cells have been shown by others to stimulate PGE2 production from fibroblasts. Other models of renal disease (renal venous constriction and glycerol-induced tubular necrosis) exhibit exaggerated PG and TxA2 release and facilitated cortical microsomal AA metabolism. These data suggest that proliferation of fibroblast-like cells and the presence of mononuclear cells may be involved in this exaggerated PG and TxA2 production underlying renal injury.