Beta Carotene Modulates Nitric Oxide Production in the Renal Ischemia/ Reperfusion Injury in Rat

Background: Renal ischemia and subsequent reperfusion injury is a major cause of acute renal failure and transplant rejection. Nitric oxide and its metabolites have important role in renal ischemia/reperfusion injury. Beta carotene as an antioxidant effectively scavenges toxic metabolites of nitric oxide. Our previous study has shown that beta carotene pretreatment protects kidney against ischemia/reperfusion injury. Objectives: In this experimental study we investigated whether effect of beta carotene is causally linked with nitric oxide signal transduction. Methods: In this experimental study, male adult Wistar rats (250 - 300 g) were exposed to 45 minutes of renal ischemia followed by 4 hours of reperfusion. Beta carotene (10, 30 and 100 mg kg-1 ) or vehicle was administered for 5 days prior to ischemia. Nitrite and nitrate were measured in the urine sample. Blood Flow and blood pressure were monitored during I/R period. Results: I/R decreased (P 0.001) urinary nitrite - nitrate and renal blood flow. Beta carotene pretreatment increased them (P 0.05 - P 0.001), although not by all doses. Blood pressure was not affected by beta carotene. Conclusions: Since beta carotene administration improved renal blood flow and reduced the injury, it seems that beta carotene exerts some of its protective effects, probably by modulating of nitric oxide system.