Toxicity of cisplatin to the central nervous system of male rabbits

The cytotoxic effects of platinum (Pt) were studied by intraparenchymal injection of 1 mg of cisplatin (CDDP) in male rabbits. Time-serial plasma Pt levels were used as CDDP clearance indices in brain and kidney tissues. The tissue samples were also examined histologically. Changes in the blood-brain barrier (BBB) were evaluated by horseradish peroxidase (HRP) extravasation. In the brain infusion group, Pt was detected in the plasma 30 min after the start of infusion. In the kidney, Pt was detected after 10 min of CDDP injection. The maximum plasma concentration of Pt in the brain group showed diffuse edema, neuronal necrosis, karyolysis, and HRP extravasation around the injection site. In contrast, the histological damage to kidneys was minimal. The results presented here show that direct infusion of CDDP caused the most extensive cytotoxicity in the brain. The low clearance rate of CDDP from the brain and BBB disruption may explain this behavior.