虚血性腎障害における尿中NAG排泄量と腎機能

抄録

The relationship of the urinary excretion of NAG (U-NAG) and the renal function (Ccr, CH₂O, FENa) was studied after various ischemic periods (30, 60, 90 and 120 min) in rabbits, to clarify the significance of U-NAG on the ischemic renal damage. (1) U-NAG showed the peak after 60 min of total renal arterial occlusion (TRAO) and gradually decreased, while the renal function gradually decreased in proportion to TRAO time. (2) The urinary excretion of γ-GTP (U-γ-GTP) remarkably increased more than U-NAG after 30 min. of TRAO. (3) Ccr markedly decreased to 17% of control and CH₂O almost drawed to zero after 120 min of TRAO. (4) Urinary flow rate significantly increased on the ischemic kidney after reflow on every other occlusion time except 120 min of TRAO, compaired with control or non ischemic kidney, but it was not related with the ischemic time. These results suggest that U-NAG reflects the extent of the ischemic renal damage by TRAO, and must be useful as the index to detect the ischemic renal damage within 60 min. of renal ischemia. However, if the ischemic time is prolonged, U-NAG does not run parallel with the renal function and ischemic time, so this index may offer false estimation. Therefore, U-NAG should be consecutively measured with the routine renal function tests, and be assessed on the base of the data. 30 min of renal ischemia may impair mainly the renal brush border membrane of proximal tubules. The acute renal failure may be caused by 120 min. of renal ischemia. Urinary flow rate is inadequate as the parameter to detect the ischemic renal damage.