Renal Reperfusion Injury: Sequential Changes in Function and Regional Albumin Extravasation

Abstract

We report on the renal function and regional extravasation of albumin-bound Evans blue dye (EB) in the kidneys of anesthetized dogs following 30 min occlusion of the left renal artery. Left kidney (LK) function was halted and no change in right kidney (RK) function was observed during ischemia. Clearances of para-amino-hippurate and inulin from the LK were significantly (P < 0.01) less than control after 10 min of reperfusion, 22.6 ± 6.8 vs 90.1 ± 7.8 and 9.0 ± 2.9 vs 34.2 ± 2.1 ml/min, respectively. Renal hemodynamic parameters never did fully recover in subsequent periods but filtration fraction was unchanged from control throughout the reperfusion period. Urine flow and sodium excretion from the LK was significantly (P < 0.01) less than control values after 10 min of reperfusion, 0.41 ± 0.14 vs 0.80 ± 0.08 ml/min and 60 ± 21 vs 161 ± 8 μeq/min, respectively, but fully recovered in subsequent periods. Significant (P < 0.01) decrease from control values in the LK content of EB was observed in the inner medulla and papilla regions after 30 min of reperfusion, 586 ± 60 vs 763 ± 51 and 549 ± 54 vs 741 ± 52 μg/EB/g dry tissue, respectively. After 60 min of reperfusion in the LK, significant (P < 0.05) changes from control in EB content were evident exclusively in the outer medulla, increasing from 398 ± 56 to 491 ± 17 μg/EB/g dry tissue, respectively. A general edema in the LK, measured as an increase in the ratio of wet/dry tissue weight, became evident only after 60 min of reperfusion. Curiously, changes in function and albumin escape became evident in the RK in the reperfusion period between 30 and 60 min. A significant drop in hemodynamic parameters is measured at the 40-min period of reperfusion and a significant elevation of albumin extravasation in the outer and inner medulla is seen subsequently at 60 min. This characterization may help in understanding the dynamic processes affecting the kidney in the period immediately following reperfusion.