Pretreatment with Olive Leaf Extract Improves Renal and Liver Antioxidant Systems Following Renal Ischemia-Reperfusion Injury in Rats

Background and Aim: The effect of Olive leaf extract (OLE) as a natural antioxidant was investigated on renal and liver antioxidant enzyme activities, after renal ischemia-reperfusion (IR) in a rat model. Materials and Methods: Forty male rats divided into 5 groups: Sham (no IR), 3 "OLE+IR" groups (25mg/kg, 50mg/kg and 100mg/kg oral OLE once daily for 2 weeks, prior to renal IR) and "water+IR" group (oral gavage of water prior to IR). In the last 4 groups, both renal pedicles clamped for 45 minutes followed by 24 hours of reperfusion. Clearance of creatinine was measured. Renal and liver catalase and glutathione peroxidase activities and glutathione level were assessed as well. Volume densities of the renal proximal convoluted tubules were measured stereologicaly. Results: Glutathione level, catalase and glutathione peroxidase activities, clearance of creatinine and volume density of the proximal convoluted tubules decreased in "water+IR" compared to the sham group. Pretreatment with OLE in 3 different doses significantly increased renal antioxidant enzymes, creatinine clearance and volume density of the proximal convoluted tubules in comparison with "water+IR" group. Pretreatment with only one dose (25mg/kg) of OLE significantly increased liver glutathione and GPx compared to the "water+IR" group. Pretreatment with 2 doses (25mg/kg, 50mg/kg) increase liver catalase compared to the water+IR group. Conclusions: Two weeks of oral pretreatment with different doses of OLE decreased renal injury couesd by renal IR. This was associated with increased renal catalase and glutathione peroxidase activities. Some doses of OLE were also associated with increased liver antioxidant system parametes.