Mechanisms of increased gastric protection after NSAID-administration in rats consuming virgin olive oil diets

SummaryThis study was aimed to know the immunomodulatory effects of defined extra virgin olive oil (EVOO) diets on indomethacin induced gastric lesion.MethodsDifferent groups were fed with diets: standard diet (5 g of fat/100 g of diet), and EVOO-5 and EVOO-20 (5 or 20 g/100 g of diet, respectively). After 6 weeks, each dietary group was divided into two, one group was treated with indomethacin and other group received vehicle only. Four hours after the animals were sacrificed and the gastric lesions were evaluated with a planimeter.ResultsMacroscopic lesions in animals fed with EVOO diets were significantly lower, with a dose–response effect (42.5 ± 1.0% and 30.7 ± 6.3%, EVOO-5 and EVOO-20 respectively, p < 0.001 vs control). Haematoxylin/eosin sections revealed that EVOO diet groups had a higher, non-quantifiable increase in mucus cells. PGE2 and GMPc levels were not modified. MPO and TNF-α values were significantly increased in animals fed the standard diet (p < 0.05 vs sham), whereas in animals fed EVOO diets these values were only slightly increased, with values close to the ones observed in controls, although without differences between groups. Significant increases in apoptotic activities (p < 0.001 vs sham), which were measured by sandwich enzyme immunoassay, were observed in the groups that received the NSAID and in animals that received only EVOO diets (EVOO-5, 73.4 ± 5.2 mU/mg prot; EVOO-20, 66.0 ± 8.7 mU/mg prot; p < 0.001 vs sham, 20.1 ± 4.3).ConclusionThis study demonstrates the beneficial role played by EVOO enriched diets with a reduction of pro-inflammatory mediators and an increase of mucus secretion and apoptotic responses.