Acute Renal Medullary Interstitial Infusion of either saline or 2% albumin indistinctly rises RIHP and RMBF in the rat

Abstract

The effects of an acute renal medullary interstitial infusion (RMII) of 100 μl of either 0.9% saline (Sal) or 2% albumin in saline (Alb) on the time course (30 min) of renal interstitial hydrostatic pressure (RIHP, subcapsular), renal medullary blood flow (RMBF, L‐D), urinary nitrogen oxides excretion (UNOxV, Griess) and urinary flow rate (V) were assessed in the left denervated kidney of anesthetized male Wistar rats under control of renal perfusion pressure at 100 mmHg. After a 10 min control period (CP) and a 15s RMII period, three 10 min post‐infusion periods (P‐IP) of urinary collections were generated. The results are mean ± SEM; ^ p<0.05 vs. CP. Group CP RMII P‐IP 10min 20 min 30 min RIHP (mmmHg) Sal 3.0 3.8 3.9 5.3 6.8 n=17 ± 0.4 ± 0.5 ±0.5^ ± 0.7^ ± 0.8^ Alb 3.0 3.2 3.5 4.0 4.8 n=17 ± 0.3 ± 0.3^ ± 0.3^ ± 0.5^ ± 0.7^ RMBF (%Δ) Sal 0.0 2.0 10.7 12.5 8.2 n=17 ± 3.4 ± 3.3^ ± 4.0 ± 4.3 Alb 0.0 2.2 9.1 6.6 8.7 n=17 ± 5.0 ± 4.5^ ± 4.7 ± 5.2 There were no differences between groups in UNOxV nor in V through time.ConclusionsAcute RMII of either 0.9% saline or 2% albumin indistinctly rises RIHP and RMBF in the anesthetized rat, without affecting UNOxV nor urinary flow rate at all. Supported by IPL's financial resources.