Effects of Olive Oil Phytochemicals and Exercise on Circulatory Leukocytes and Inflammation in Atherosclerotic Rats

Oleocanthal (Oleo) and Oleacein (Olea) are natural phenolic compounds found in extra-virgin olive oil (EVOO), exerting anti-inflammatory and antioxidant effects. Atherosclerosis, led by arterial plaque deposition, involves increased chronic inflammation and oxidative stress. PURPOSE: The purpose of the study is to evaluate the immuno-regulatory and anti-inflammatory effects of Oleo/Olea supplementation and exercise training in the atherosclerotic rats. METHODS: Female Sprague-Dawley rats (age 4-week, n=48) were randomly divided into 4 groups fed an atherogenic diet (C) with added cholesterol (1.25%) and cholic acid (0.5%) for 12 wks. Half of the rats were supplemented with high Oleo/Olea (1000 mg/kg, HO, n=24); the other half with low Oleo/Olea (100 mg/kg, LO, n=24). In each dietary group, half group was trained (T) on treadmill for 12 wks (25m/min, 10% grade for 60 min/day, 5 days/wk), while the other half remained sedentary (S). Two separate groups of rats were fed a chow diet (n=6) and atherogenic diet (n=12), respectively without EVOO or T. Total leukocytes and differential were measured using flow cytometry. Total nitrate/nitrite (NOx) contents were determined by colorimetric assay kit. Data were shown as mean ± SEM and analyzed using two-way ANOVA. RESULTS: Leukocytes percentage was higher in HO vs. LO rats (P<0.05), but lowered 32% by T (P<0.05). LO and HO rats showed higher granulocytes percentage than C rats (P<0.05), whereas T suppressed granulocytes in HO by 27% (P<0.05). Neutrophils percentage was increased in HO vs. C and LO rats (P<0.05), but declined by 41% with T (P<0.01). Lymphocytes percentage was decreased in LO and HO rats (P<0.05) and elevated in HO+T by 23% (P<0.05). In addition, T tended to increase monocytes levels in LO rats (0.05