Virgin olive oil administration improves the effect of aspirin on retinal vascular pattern in experimental diabetes mellitus.

The aim of the present study is to evaluate the possible influence of virgin olive oil (VOO) on the effect of acetylsalicylic acid (ASA) in platelet aggregation, prostanoid and NO production and retinal vascular pattern in rats with experimental type 1-like diabetes. We used 100 male Wistar rats that were distributed into five groups: (1) non-diabetic rats (NDR); (2) untreated diabetic rats (DR); (3) DR treated with ASA (2 mg/kg per d per os (p.o.)); (4) DR treated with VOO (0.5 ml/kg per d p.o.); (5) DR treated with ASA plus VOO. The duration of diabetes was 3 months, and each treatment was administered from the first day of diabetes. Variables that were quantified were platelet aggregation (I(max)), thromboxane B(2) (TxB(2)), aortic prostacyclin (6-keto-PGF(1alpha)) and NO, and the percentage of retina with horseradish peroxidase-permeable vessels (HRP-PV). Diabetic rats showed a higher I(max) (35 %) and TxB(2) (63 %) than NDR, and a lower 6-keto-PGF(1alpha), NO and HRP-PV than NDR ( - 74.6 %). ASA and VOO administration reduced these differences and prevented the percentage of HRP-PV ( - 59.7 % with ASA and - 46.7 % with VOO). The administration of ASA plus VOO showed a strong platelet inhibition (80.2 v. 23.4 % for VOO and 50.6 % for ASA+VOO, P < 0.0001), and reduced HRP-PV differences to - 31.6 % (P < 0.001 with respect to DR and P < 0.0001 with respect to DR treated with ASA). In conclusion, the administration of VOO to rats with type 1-like diabetes mellitus improves the pharmacodynamic profile of ASA, and increases its retinal anti-ischaemic effect.

Effect of virgin olive oil plus acetylsalicylic acid on brain slices damage after hypoxia-reoxygenation in rats with type 1-like diabetes mellitus.

Aspirin is the most widely used drug for the secondary prevention of ischemic stroke in patients suffering from diabetes mellitus. Moreover virgin olive oil (VOO) administration exerts a neuroprotective effect in healthy rat brain slices. The aim of the present study was to determine the possible influence of VOO administration to streptozotocin-diabetic rats (DR) on the neuroprotective effect of aspirin in rat brain. DR were treated during 3 months with saline, aspirin (2mg/kg/day p.o.), VOO (0.5 mL/kg/day p.o.) or its association; a control normoglycemic group was treated with saline. Brain slices were subjected to oxygen-glucose deprivation before a reoxygenation period. All the treatments significantly reduced lactate dehydrogenase LDH efflux after reoxygenation (-54.1% for aspirin, -51.3% for VOO and -72.9% for aspirin plus VOO). Lipid peroxides in brain slices were also reduced after the treatment with aspirin (-17.90%), VOO (-37.3%) and aspirin plus VOO (-49.2%). Production of nitric oxide after reoxygenation was inhibited by all the treatments (-46.5% for ASA, -48.2% for VOO and -75.8% for ASA plus VOO). The activity of the inducible isoform (iNOS) was inhibited by the three types of treatment (-31.8% for ASA, -29.1% for VOO and -56.0% for ASA plus VOO). The main conclusion of our study is that daily oral administration of VOO to diabetic rats may be a natural way to increase the neuroprotective effect of aspirin in diabetic animals.