The long‐term outcome of post‐ischaemic acute renal failure in the rat. I. A functional study after treatment with SOD and sucrose

Abstract

The long-term outcome in rat kidneys subjected to 45 min of warm ischaemia with no treatment and after administration of 20 mg superoxide dismutase (SOD) and of SOD combined with 2 ml of a 12% sucrose solution was studied by the micropuncture technique. It was found that, although in the acute phase SOD prevented trapping of erythrocytes in the medullary vasculature and that SOD + sucrose also prevented the formation of tubular obstruction, the long-term results as studied I week and I month after the primary ischaemic insult were virtually identical. This was due to the formation of new obstruction, during the first week, mainly in the thick ascending limb of Henle''s loop. After I month the proximal tubular free-flow pressure and the single-nephron filtration rate had returned to normal. However, since the total glomerular filtration was only one-third of that under normal conditions, it would seem that two-thirds of the nephrons had undergone complete degeneration. This degeneration was probably the result of persistent tubular obstruction. The tubular degeneration was also accompanied by a reduction in urine osmolality and potassium secretion.