Dietary fish oil supplement induces age-specific contractile and proteomic responses in muscles of male rats

Abstract

Background: Dietary fish oil (DFO) has been identified as a micronutrient supplement with the potential to improve musculoskeletal health in old age. Few data are available for effects of DFO on muscle contractility, despite the significant negative impact of muscle weakness on age-related health outcomes. Accordingly, the effects of a DFO intervention on the contractile function and proteomic profile of adult and aged in an animal model of aging were investigated. Methods: This preliminary study evaluated 14 adult (8 months) and 12 aged (22 months) male, Sprague-Dawley rats consuming a DFO-supplemented diet or a control diet for 8 weeks (7 adult and 6 aged/dietary group). Animal weight, food intake and grip strength were assessed at the start and end of the FO intervention. In situ force and contractile properties were measured in the medial gastrocnemius muscle following the intervention and muscles were processed for 2-D gel electrophoresis and proteomic analysis via liquid chromatography with tandem mass spectrometry, confirmed by immunoblotting. Effects of age, diet and age x diet interaction were evaluated by 2way ANOVA. Results: A significant (P = 0.022) main effect for DFO to increase (~15%) muscle contractile force was observed, without changes in muscle mass. Proteomic analysis revealed a small number of proteins that differed across age and dietary groups at least 2-fold, most of which related to metabolism and oxidative stress. In seven of these proteins (creatine kinase, triosephosphate isomerase, pyruvate kinase, parvalbumin, beta-enolase, NADH dehydrogenase and Parkin7/DJ1), immunoblotting corroborated these findings. Parvalbumin showed only an effect of diet (increased with DFO) (P = 0.003). Significant age x diet interactions were observed in the other proteins, generally demonstrating increased expression in adult and decreased expression aged rats consuming DFO (all P > 0.011). However, correlational analyses revealed no significant associations between contractile parameters and protein abundances.

Potential of Fatty Acids in Treating Sarcopenia: A Systematic Review

“…There were 10 pre-clinical studies, including 3 cell experiments [ 14 , 17 , 40 ] and 7 animal studies [ 18 , 41 , 42 , 43 , 44 , 45 , 46 ]. Refer to Table 2 and Table 3 .…”

“…One study [ 43 ] used the senescence-accelerated SAMP8 mouse ( n = 51), two studies [ 18 , 46 ] used Wistar rats, and one used [ 44 ] Sprague Dawley rats. Five studies [ 18 , 41 , 43 , 45 , 46 ] had young mice or rats aged from 25 weeks to 8 months as positive control groups, and in the experimental group, elderly mice or rats had an age range from 15 months to 24 months. EPA [ 41 , 44 ], DHA [ 41 ], ClA [ 42 ], dietary fish oil [ 45 ], and olive leaf extracts [ 18 , 46 ] were used as interventions in the animal studies, and all fatty acids showed a positive effect on old mice or rats.…”

“…Five studies [ 18 , 41 , 43 , 45 , 46 ] had young mice or rats aged from 25 weeks to 8 months as positive control groups, and in the experimental group, elderly mice or rats had an age range from 15 months to 24 months. EPA [ 41 , 44 ], DHA [ 41 ], ClA [ 42 ], dietary fish oil [ 45 ], and olive leaf extracts [ 18 , 46 ] were used as interventions in the animal studies, and all fatty acids showed a positive effect on old mice or rats. One study [ 43 ] used trans-fatty acids (from partially hydrogenated vegetable oil, mainly trans-18:1) and found no significant effects on diet or interactions in mice.…”

“…Only two studies [ 42 , 43 ] assessed muscle mass and strength. Grip strength was commonly used in measuring muscle physical performance in the studies [ 43 , 44 , 45 ]. Most studies [ 18 , 41 , 44 , 45 , 46 ] used qPCR to assess gene expression and histological analysis.…”

“…Only two studies [42,43] assessed muscle mass and strength. Grip strength was commonly used in measuring muscle physical performance in the studies [43][44][45].…”