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.

Keywords:

• Nutraceuticals
• inflammation
• docosahexaenoic acid
• eicosapentaenoic acid
• omega-3 PUFAs
• cyclooxygenase

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Funding

This study was supported by grants from CAPES–Brazil (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), FINEP–Brazil (Financiadora de Estudos e Projetos), and CNPq–Brazil (Conselho Nacional de Desenvolvimento Cientıfico e Tecnológico). A.G.D was recipient of an undergraduate fellowship from CNPq; G.T was recipient of a PhD fellowship from CAPES–Brazil; L.F. was recipient of a senior research fellowship from CNPq.