Short‐ and Long‐Term Effects of Dietary Supplementation with Fish Oil on Inflammatory Pain in Rats

Abstract

Introduction Dietary supplementation with fish oil is promising as a complementary therapy for inflammatory pain. However, further studies are needed to support its therapeutic potential. For example, the antinociceptive effect of fish oil is widely suggested to be dependent on decreased prostaglandin E2 (PGE2) synthesis, but no previous study has investigated if it affects PGE2-induced nociceptive response. Similarly, beneficial long-term effects on inflammatory response are related to early exposure to fish oil, however, whether these effects include decreased inflammatory pain throughout life is not known. Objective The aim of this study was to investigate the short- and long-term effects of fish oil on inflammatory pain. Methods Dietary fish oil supplementation was performed through two protocols: in adult rats, during 20 days, or in dams, during pregnancy and lactation, with tests performed in adult offspring. The hyperalgesic response induced by carrageenan and its final mediators PGE2 and norepinephrine was used to model inflammatory pain. Results The findings demonstrated for the first time that dietary fish oil (1) decreases the hyperalgesia induced by carrageenan; (2) but not that induced by its final mediator PGE2 and norepinephrine; (3) increase omega-3 polyunsaturated fatty acids in peripheral neural tissue; and (4) attenuates inflammatory pain in individuals exposed to fish oil during pre-natal life and lactation. Conclusion Together, these findings support that fish oil decreases inflammatory pain either when consumed during adult life or during prenatal development. Future studies should confirm the therapeutic potential of fish oil in humans, which is essential for the development of public policies to encourage a fish oil richer diet.