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. 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 2-way ANOVA. 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. Results of this preliminary study support the hypothesis that DFO can enhance musculoskeletal health in adult and aged muscles, given the observed improvement in contractile function. The fish oil supplement also alters protein expression in an age-specific manner, but the relationship between proteomic and contractile responses remains unclear. Further investigation to better understand the magnitude and mechanisms muscular effects of DFO in aged populations is warranted.

中文翻译：

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膳食鱼油补充剂可在雄性大鼠的肌肉中诱导特定年龄的收缩和蛋白质组反应。

膳食鱼油（DFO）已被确认为微量营养补充剂，具有改善老年肌肉骨骼健康的潜力。尽管肌肉无力对与年龄有关的健康结局有重大负面影响，但很少有数据可用于DFO对肌肉收缩的影响。因此，在衰老动物模型中，研究了DFO干预对成年人和老年人的收缩功能和蛋白质组学特征的影响。这项初步研究评估了14只成年（8个月）和12只年龄（22个月）的雄性Sprague-Dawley大鼠，它们补充了DFO饮食或对照饮食8周（7个成年和6个年龄/饮食组）。在FO干预开始和结束时评估动物的体重，食物摄入量和握力。干预后在腓肠内侧肌中测量原位力和收缩特性，并通过液相色谱和串联质谱对肌肉进行2-D凝胶电泳和蛋白质组学分析，并通过免疫印迹进行确认。年龄，饮食和年龄x饮食相互作用的影响通过2向ANOVA进行评估。观察到DFO增加（〜15％）肌肉收缩力的显着（P = 0.022）主要作用，而肌肉质量没有变化。蛋白质组学分析显示，少数蛋白质在年龄和饮食组之间差异至少2倍，其中大多数与代谢和氧化应激有关。在其中的7种蛋白质（肌酸激酶，磷酸三糖异构酶，丙酮酸激酶，小白蛋白，β-烯醇酶，NADH脱氢酶和Parkin7 / DJ1）中，免疫印迹证实了这些发现。小白蛋白仅显示饮食效果（DFO增加）（P = 0.003）。在其他蛋白质中观察到了显着的年龄x饮食相互作用，通常表明在成人中表达增加而在消耗DFO的老年大鼠中表达降低（所有P> 0.011）。然而，相关分析表明收缩参数和蛋白质丰度之间没有显着关联。这项初步研究的结果支持以下假设：鉴于观察到的收缩功能改善，DFO可以增强成年和老年肌肉的骨骼肌肉健康。鱼油补充剂还以特定年龄的方式改变蛋白质表达，但是蛋白质组学和收缩反应之间的关系仍然不清楚。