Chronic lithium treatment protects the rat kidney against ischemia/reperfusion injury: The role of nitric oxide and cyclooxygenase pathways

Ischemia/reperfusion injury is a major problem in renal transplantation. Several evidences represent lithium preconditioning effect against ischemia/reperfusion injury in various tissues. In this study our aim was to investigate the protective effect of chronic lithium administration on renal ischemia/reperfusion injury in rats. Ischemia/reperfusion injury was induced by clamping left renal pedicle for 60min, 2weeks after right nephrectomy. Lithium-treated animals received lithium-chloride in drinking water for 30days. In order to investigate the role of nitric oxide (NO) and cyclooxygenase (COX) pathways in renoprotective effect of lithium, N_ω-nitro-L-arginine methyl ester hydrochloride (L-NAME, NO synthase inhibitor) and indomethacin (COX inhibitor) were used, respectively. Serum creatinine, blood urea nitrogen and renal histology were assessed 24h after inducing ischemia/reperfusion injury. Dimercaptosuccinic acid scan was also performed 48h following operation. Chronic lithium treatment in ischemia/reperfusion injury groups significantly decreased creatinine (1.09±0.16mg/dl), blood urea nitrogen (59.0±13.38mg/dl), histological damage (7.83%±4.02%) and improved cortical function compared with non-lithium treated animals (4.45±0.44, 176.66±12.24mg/dl and 83.5%±3.5%, respectively) (P<0.001). Either L-NAME or indomethacin administration partially reversed the protective effect of lithium, while simultaneous blockade of NO and COX pathways completely abolished lithium renoprotective effect. Our results indicate that lithium ameliorates renal ischemia/reperfusion injury through NO and/or COX pathways. We propose that lithium pre-treatment as a simple and practical intervention to boost the renal viability and function after ischemia/reperfusion injury may be promising in the setting of transplantation.