Cisplatin nephrotoxicity: in vitro studies with precision-cut rabbit renal cortical slices

Severe nephrotoxic side effects limit the use of cisplatin, a potent anticancer drug. In this study, precision-cut renal cortical slices from rabbits were evaluated as a cisplatin nephrotoxicity model. Cortical slices accumulated approximately 180 ppm (195 ppm Pt = 10(-3) M) of platinum(II) after 18 hr of incubation in medium containing 10(-3) M cisplatin. Dose- and time-dependent toxic responses for clinically relevant concentrations of cisplatin (10(-3)-10(-5) M) were apparent using leakage of intracellular K+, ATP, and lactate dehydrogenase (LDH) to determine cell damage. Histopathologic changes were also produced. Intracellular ATP levels dropped significantly after 6 hr of incubation in 10(-3) M cisplatin, and after 12 hr with 10(-4) M cisplatin. Similarly, intracellular K+ levels decreased significantly by 6 hr of incubation with 10(-3) M cisplatin but remained at control levels for 18 hr in the presence of 10(-4) M cisplatin. Decrements in intracellular LDH levels were not seen until after 12 hr of incubation in 10(-3) M cisplatin. The noncytotoxic isomer transplatin at 10(-3) M was not accumulated by slices; however, intracellular ATP levels were depressed. Of the viability parameters evaluated, intracellular K+ and ATP were found to be optimal indicators. Other active platinum analogs, carboplatin and iproplatin, also caused dose- and time-dependent leakage of intracellular K+ and ATP from renal cortical slices. The ranking of nephrotoxicity of the platinate compounds within this system at concentrations adjusted to approximate equivalent therapeutic activity was similar to that observed in vivo (cisplatin = iproplatin greater than carboplatin greater than transplatin). These results suggest that precision-cut renal cortical slices comprise a viable in vitro model for platinum-induced nephrotoxicity studies.