The Effectiveness of Fish Oil Supplementation in Asthmatic Rats is Limited by an Inefficient Action on ASM Function

Abstract

Episodes of acute exacerbation are the major clinical feature of asthma and therefore represent an important focus for developing novel therapies for this disease. There are many reports that the n-3 fatty acids found in fish oil exert anti-inflammatory effects, but there are few studies of the action of fish oil on airway smooth muscle (ASM) function. In the present investigation, we evaluated the effect of fish oil supplementation on smooth muscle force of contraction in ovalbumin-induced asthmatic Wistar rats, and its consequences on static lung compliance, mucus production, leukocyte chemotaxis and production of proinflammatory cytokines. Fish oil supplementation suppressed the infiltration of inflammatory cells into the lung in asthmatic animals (2.04 ± 0.19 × 10(6) cells vs. 3.33 ± 0.43 × 10(6) cells in the control asthmatic group; P < 0.05). Static lung compliance increased with fish oil supplementation in asthmatic rats (0.640 ± 0.053 mL/cm H2O vs. 0.399 ± 0.043 mL/cm H2O; P < 0.05). However, fish oil did not prevent asthma-associated lung eosinophilia and did not affect the concentrations of tumor necrosis factor-α and interleukin-1β in lung tissue or the proportion of the airways obliterated with mucus. Fish oil had no effect on the force of contraction in asthmatic rats in response to acetylcholine (3.026 ± 0.274 mN vs. 2.813 ± 0.364 mN in the control asthmatic group). In conclusion, although fish oil exerts some benefits in this model of asthma, its effectiveness appears to be limited by an inefficient action on airway smooth muscle function.

An International Survey of Aquaponics Practitioners

“…A common protein source in fish feed is fishmeal made from small pelagic fish like herring or sardines [32], which has measurable environmental, social, and economic costs [33]–[35]. Other fields of aquaculture are attempting to reduce or eliminate fishmeal and fish oil from feed [36], [37]. Aquaponic operators should continue reducing the use of fishmeal and fish oil as well, which is easier in fish species that are herbivorous or omnivorous.…”

A systematic review of the association between fish oil supplementation and the development of asthma exacerbations

“…Bargut et al’s 12 study reflected significantly attenuated mucus production in the ovalbumin (OVA)-exposed fish oil group when compared to the OVA-exposed control group (p < 0.0001). However, Miranda et al’s 10 study showed no significant change in airway mucus levels between the fish oil and control groups.…”

“…In addition, the use of fish oil reduced antigen-induced lung hyperreactivity (p < 0.05). 12 Miranda et al’s 10 rat model demonstrated a significant increase in static lung compliance in fish-oil supplemented, asthmatic rats (p < 0.05); however, there was no significant variation between the post-exposure groups in pulmonary smooth muscle force of contraction or smooth muscle layer thickness. Eliaçik et al’s 14 model found that basement membrane thickness was significantly lowered after fish oil supplementation (p = 0.038), but found no significant difference in goblet cell numbers or subepithelial smooth muscle thickness of airways between the groups.…”

“…Miranda et al’s 10 study reflected no significant difference in TNF-α levels among fish oil or placebo groups. However, Schuster et al’s study showed significantly lower TNF-α concentrations in all three n-3 PUFA groups tested as compared to the control group.…”

“…Bargut et al 12 (1.075 EPA:DHA ratio), Miranda et al 10 (unreported EPA:DHA ratio), Eliaçik et al 14 (2.5 EPA:DHA ratio), and Schuster et al 11 (DHA, only; EPA, only; and 1:1, EPA:DHA formulations) all studied the components of the lung to determine the alterations post-exposure to an irritant to determine if the use of fish oil affected the composition of pulmonary structures. In Bargut et al’s 12 mice study, results showed a significant reduction in peribronchiolar matrix deposition post-antigen exposure (p = 0.0099).…”