Influence of a diet rich in eicosapentaenoic acid on the development of rat paw oedema and on the formation of prostaglandins I2 and E2

Abstract

The influence of feeding a marine oil (MaxEPA) with a high content of eicosapentaenoic acid (EPA) to rats for 10 weeks on the development of carrageenin oedema was studied. Since prostaglandins (PGs) are involved in the development of this acute experimental inflammation, the influence of EPA feeding on PG release from aorta (PGI2) and from the subplantar skin of the inflamed foot (PGI2, PGE2) was investigated also. MaxEPA was fed in two daily doses containing 50 or 100 mg EPA/kg/day. In both rat groups there was no influence of EPA on the development of the oedema. However, the capacity of aorta and skin of the plantar region of the experimentally inflamed foot to release PGI2 was strongly reduced by EPA. On the other hand, the release of PGE2 from the skin was not reduced. Indomethacin at a low dose (2 mg/kg perorally) reduced the development of the paw oedema as well as the release of PGs in control rats and rats on an EPA-containing diet. It is concluded that EPA did not influence carrageenin oedema because there was an adequate production of the oedema promoting substance PGE2.

Effect of a Fish-Oil-Supplemented Diet on Inflammation and Immunological Processes in Rats

“…They also showed that pro duction of PGE2 in the plantar region of the inflamed foot was not influenced by EPA. Our data showing no effect of the fatty-acid-enriched diet on the exudative reaction and the synthesis of PGE2 in acute inflamma tion support those reported by Sametz and Juan [37], On the other hand, our finding that the EPA-and DCHA-enriched diet did not affect cell migration and LTB4 production in the acute phase of inflammation was consistent with the finding of Terano et al [36].…”

“…However, Terano et al [36] also reported that there was no effect of EPA on the concentration of LTB4 and cell numbers in the exudate. Conversely, Sametz and Juan [37] reported that rats fed a marine oil containing 50 or 100 mg/kg/day of EPA for 10 weeks demonstrated no difference in hindpaw edema induced by carrageenin. They also showed that pro duction of PGE2 in the plantar region of the inflamed foot was not influenced by EPA.…”

n‐3 fatty acids and leucocytes

“…Supplementation with fish oil resulted in reduced levels of PGE, and LTB, together with an increased amount of monocytes and macrophages in inflammatory exudate in chronic inflammation. This is in agreement with another study [57] but in contrast to the findings of Terano and associates [58], who found that n-3 PUFAs inhibited tissue inflammation, without changing cell numbers and LTB, in the inflammatory exudate. PGE, and TXB, however decreased while LTB, increased in the exudate after n-3 PUFAs.…”

The Influences of Casein Phosphopeptides on Metabolism of Ectopic Bone Induced by Docosahexaenoic Acids on Acute Inflammation and Fatty Acid Composition in Rats.

“…Besides, the concentrations of leukotriene B4 (LTB4) in the exudate tended to be reduced. Sametz et al (9) reported that administration of a marine oil in a dose of 50 or 100mg EPA/kg/day for 10 weeks strongly reduced PGI2 production but not PGE2 production by inflamed skin, and that either dose of EPA did not influence carrageenan-induced edema. Yoshino and Ellis (10) employed a higher dose of n-3 HUFA, 500mg EPA/kg/day and 333 mg DHA/kg/day, and fed rats for 50days.…”

“…This discrepancy is probably explained by large differences in n-3 HUFA doses. Sametz et al (9) employed a dose of 100mg EPA/kg/day at most; Yoshino and Ellis (10) employed a dose of 833mg (EPA+DHA)/kg/day. These doses were much smaller than our dose of 4g n-3 HUFA/kg/day.…”