The neuroprotective effect of olive leaf extract is related to improved blood-brain barrier permeability and brain edema in rat with experimental focal cerebral ischemia

Recent studies suggest that olive extracts suppress inflammation and reduce stress oxidative injury. We sought to extend these observations in an in vivo study of rat cerebral ischemia-reperfusion injury. Four groups, each of 18 Wister rats, were studied. One (control) group received distilled water, while three treatment groups received oral olive leaf extract (50, 75 and 100 mg/kg/day respectively). After 30 days, blood lipid profiles were determined, before a 60 mm period of middle cerebral artery occlusion (MCAO). After 24 h reperfusion, neurological deficit scores, infarct volume, brain edema, and blood-brain barrier permeability were each assessed in subgroups of six animals drawn from each main group. Olive leaf extract reduced the LDL/HDL ratio in doses 50, 75, and 100 mg/kg/day in comparison to the control group (P < 0.001), and offered cerebroprotection from ischemia-reperfusion. For controls vs. doses of 50 mg/kg/day vs. 75 mg/kg/day vs. 100 mg/kg/day, attenuated corrected infarct volumes were 209.79 +/- 33.05 mm(3) vs. 164.36 +/- 13.44 mm(3) vs. 123.06 +/- 28.83 mm(3) vs. 94.71 +/- 33.03 mm(3); brain water content of the infarcted hemisphere 82.33 +/- 0.33% vs. 81.33 +/- 0.66% vs. 80.75 +/- 0.6% vs. 80.16 +/- 0.47%, and blood-brain barrier permeability of the infarcted hemisphere 11.22 +/- 2.19 mu g/g vs. 9.56 +/- 1.74 mu g/g vs. 6.99 +/- 1.48 mu g/g vs. 5.94 +/- 1.73 mu g/g tissue (P<0.05 and P<0.01 for measures in doses 75 and 100 mg/kg/day vs. controls respectively). Oral administration of olive leaf extract reduces infarct volume, brain edema, blood-brain barrier permeability, and improves neurologic deficit scores after transient middle cerebral artery occlusion in rats. (C) 2010 Elsevier GmbH. All rights reserved.