Modulated function of multidrug resistance-associated proteins in cisplatin-induced acute renal failure rats

The effect of cisplatin-induced acute renal failure (ARF) on the function and expression of multidrug resistanceassociated proteins (MRPs) was evaluated in rats. Rats received an intraperitoneal injection of cisplatin (9 mg/kg), and the induction of ARF state with high plasma concentrations of indoxyl sulfate and creatinine was observed 72 h after cisplatin treatment. The function of MRPs in the liver, kidney and brain was evaluated by measuring the tissue accumulation and biliary excretion of 2,4-dintrophenyl-S-glutathione (DNP-SG), a substrate for MRPs, after administration of 1-chloro-2,4-dintrobenzene (CDNB), a precursor of DNP-SG, in rats. The levels of MRP1-4 expression were evaluated by Western blot analysis. Effect of ARF plasma components on MRP function was also examined by using calcein acetoxymethyl ester (calcein-AM) in HepG2 cells. In ARF rats (72 h after cisplatin treatment), the accumulation of DNP-SG in the liver, kidney and brain was significantly higher than those in control and cisplatin-treated rats (1 h after treatment). In ARF rats, intrinsic biliary excretion clearance of DNP-SG, estimated by dividing the biliary excretion rate of DNP-SG with the liver concentration, was also significantly reduced, though the expression levels of MRP1-4 in the liver remained unchanged. ARF rat plasma (5%) significantly increased the accumulation of calcein, a MRP substrate, in HepG2 cells after application of calcein-AM. In conclusion, MRP function was found to be suppressed not only in the kidney but also in the liver and brain in cisplatin-induced ARF rats, possibly due to the accumulation of some MRP substrates/inhibitors in plasma.