J. Oaz1 mediate renal tubular uptake of IS in basolateral membrane, were markedly downregulated by renal I/R, but restored by SULT inhibitors. Our results suggest that renal accumulation of IS in ischemic AKI induces oxidative stress and downregulation of organic anion transporters resulting in kidney damage, which could be restored to some extent by inhibiting hepatic SULT activity as a nephropreventive target. (Niwa, 2010, 2011). Following intestinal absorption, indole is hydroxylated to indoxyl by cytochrome P450 (CYP) 2E1 or CYP2A6, and subsequently conjugated to IS by sulfotransferase (SULT) 1A1 in the liver (Banoglu and King, 2002; Banoglu screening assay were analyzed by HPLC using a gradient as described later. Measurement of urine kidney injury molecule (Kim)-1 Urine samples were collected periodically from rats in metabolic cages 3C48 h after I/R treatment. Kim-1 concentration in urine was determined by using a Tim-1/Kim-1/HAVCR Immunoassay kit (R&D Systems, Inc., MN) (Kusumoto 0.01 versus sham (control); ## 0.01 versus I/R. Effect of AST-120, SULT Inhibitors, and Sulforaphane on Kim-1 Excretion in Urine In order to clarify whether I/R-induced AKI was related to renal tubular cell damage, the preventive effect of AST-120, SULT inhibitors, or sulforaphane on urinary excretion of renal proximal tubule-specific biomarker Kim-1 was explored. Urinary Kim-1 excretion was markedly elevated in rats with renal I/R compared with that in control rats (Fig. ?(Fig.2A).2A). Oral administration of AST-120, resveratrol, and sulforaphane significantly decreased urinary excretion of Kim-1 (Figs. ?(Figs.2B,2B, ?,C,C, ?,E,E, and ?andF).F). These observations suggested that the IS accumulation in the ischemic kidney could contribute to the progression or development of renal proximal tubule injury, and the compounds that suppress IS production and/or accumulation may help prevent renal tubular damage. To our surprise, quercetin showed no protective effect on urinary Kim-1 excretion (Fig. ?(Fig.2D),2D), despite displaying a significant nephropreventive effect as observed by the restored SCr and BUN levels in renal ischemic rats. Open in a separate window FIG. 2. Effect of AST-120, SULT inhibitors, and sulforaphane on Kim-1 excretion in urine. Urinary Kim-1 Nifenalol HCl excretion was determined in rats with (A, solid circle) or without renal I/R treatment (A, open circle). AST-120 (B), resveratrol (C), quercetin (D), and sulforaphane (E) were orally administered to rats 24 and 1 h before and 24 h after renal I/R. Urine samples were collected periodically after I/R treatment. Urinary excretion of Kim-1 in each group at 48 h is depicted (F). Each line (ACE) represents the mean value of urinary Kim-1 excretion. Each column (F) represents the mean Nifenalol HCl SD for 4C6 rats in each group. ** 0.01 versus sham (control); ## 0.01 versus I/R. Effect of Postoral Administration of AST-120 and SULT Inhibitors on Renal Function and IS Concentration in Serum and Kidney of Rats after Renal I/R Treatment We also investigated the effect of commencing oral administration of the compounds 3, 6, and 24 h after renal I/R treatment. Postadministration of AST-120, but not resveratrol or quercetin, resulted in a significant decrease in serum IS level (Fig. ?(Fig.3C).3C). However, AST-120 had no significant effect on the level of SCr or BUN (Figs. ?(Figs.3A3A and?B). The increased excretion of urinary Kim-1 in I/R rats was unaffected by the postadministration of these test compounds (Fig. ?(Fig.3D).3D). Our observations suggest the Nifenalol HCl administration of Nifenalol HCl a compound that suppresses IS accumulation prior to I/R of the kidney might be required in order to prevent the onset of ischemic AKI. Open in a separate window FIG. 3. Effect of postoral administration of AST-120 and SULT inhibitors on renal function and IS concentration in serum and kidney of rats after renal I/R treatment. AST-120 and SULT inhibitors were orally administered to rats 3, 6, and 24 h after renal I/R. After I/R.