Laboratory of Exercise and Sports Nutrition (LESN), Department of Kinesiology, The University of Texas at San Antonio, San Antonio, TX, 78249, USA.
Laboratory of Physiological Hygiene and Exercise Science (LPHES), School of Kinesiology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA.
J Int Soc Sports Nutr. 2020 Jul 25;17(1):41. doi: 10.1186/s12970-020-00368-3.
Avenanthramides (AVA) are a group of di-phenolic acids found only in oats and have shown antioxidant and anti-inflammatory effects in vitro and in vivo. Eccentric muscle contraction is intimately involved in rigorous exercise that activates systemic and local inflammatory responses. The objective of the study is to evaluate whether chronic AVA supplementation could attenuate peripheral inflammatory and immunological markers in human subjects in response to an acute bout of downhill running (DR).
Eleven male and thirteen female subjects voluntarily participated in this double-blinded, randomized controlled study and were randomly divided into AVA-supplemented (AVA) or control (C) groups. All subjects conducted a DR protocol at - 10% grade with an intensity equivalent to 75% of their maximal heart rate. Blood samples were collected at rest and various time points (0-72 h) after DR (PRE). After an 8-week washout period, participants received two cookies daily containing either 206 mg/kg (AVA) or 0 mg/kg (C) AVA for 8 weeks. Following the oat supplementation regimen, the DR and blood sampling protocols were repeated (POST). Plasma inflammatory and immunological markers were measured using Multiplex immunoassay and muscle soreness was evaluated with pain rating scale.
DR increased plasma creatine kinase (CK) activity (P < 0.01) during PRE, but the response was reduced at 24 and 48 h during POST vs. PRE regardless of AVA status (P < 0.05). Neutrophil respiratory burst (NRB) levels were elevated at 4 and 24 h (P < 0.05) during PRE but were significantly decreased at 0-48 h during POST vs. PRE (P < 0.05 or 0.01). Granulocyte-colony stimulating factor (G-CSF), the neutrophil stimulating cytokine, was also increased in response to DR but showed lower levels in AVA compared to C during POST vs. PRE (P < 0.05). Plasma interleukin-6 (IL-6) content showed an increase at 0 and 4 h during PRE and 0 h during POST (P < 0.01), whereas during POST there was a trend toward a lower IL-6 level in AVA vs. C (P = 0.082). Plasma levels of anti-inflammatory agent interleukin-1 receptor antagonist (IL-1Ra) showed an increase at 4 h during PRE, and was significantly elevated in AVA vs. C during POST. Both soluble vascular cell adhesion molecule-1 (sVCAM-1) and monocyte chemoattractant protein-1 (MCP-1) contents increased at 0 and 24 h post DR during PRE as well as POST sessions, however, sVCAM-1 content was lower in AVA vs. C during POST (P < 0.05) and MCP-1 levels were below resting level at 24, 48 and 72 h during POST (P < 0.05). DR increased muscle pain at all post-DR time points (P < 0.01), but the pain level was alleviated by oat supplementation at 48 and 72 h during POST regardless of AVA treatment (P < 0.05).
Oat AVA supplementation reduced circulatory inflammatory cytokines and inhibited expression of chemokines and cell adhesion molecules induced by DR.
ClinicalTrials.gov identifier: NCT02584946 . Registered 23 October 2015.
燕麦素（AVA）是仅在燕麦中发现的一组二酚酸，已在体外和体内显示出抗氧化和抗炎作用。离心肌肉收缩与激活全身和局部炎症反应的剧烈运动密切相关。本研究的目的是评估慢性 AVA 补充是否可以减轻人类受试者在急性下坡跑步（DR）后的外周炎症和免疫标志物。
11 名男性和 13 名女性受试者自愿参加这项双盲、随机对照研究，并随机分为 AVA 补充（AVA）或对照（C）组。所有受试者均以-10%的坡度进行 DR 方案，强度相当于最大心率的 75%。在 DR（PRE）前、后 0-72 小时（POST）的不同时间点采集血样。经过 8 周的洗脱期后，参与者每天服用两片含有 206mg/kg（AVA）或 0mg/kg（C）AVA 的饼干 8 周。在 oat 补充方案结束后，重复 DR 和采血方案（POST）。使用多重免疫测定法测量血浆炎症和免疫标志物，并用疼痛评分量表评估肌肉酸痛。
DR 在 PRE 期间增加了血浆肌酸激酶（CK）活性（P<0.01），但在 POST 期间的 24 和 48 小时时，AVA 状态对反应没有影响（P<0.05）。中性粒细胞呼吸爆发（NRB）水平在 PRE 的 4 和 24 小时升高（P<0.05），但在 POST 的 0-48 小时内明显低于 PRE（P<0.05 或 0.01）。粒细胞集落刺激因子（G-CSF），一种刺激中性粒细胞的细胞因子，也因 DR 而增加，但在 POST 期间 AVA 组与 C 组相比水平较低（P<0.05）。血浆白细胞介素-6（IL-6）含量在 PRE 的 0 和 4 小时以及 POST 的 0 小时增加（P<0.01），而在 POST 期间 AVA 组与 C 组相比，IL-6 水平呈下降趋势（P=0.082）。抗炎剂白细胞介素-1受体拮抗剂（IL-1Ra）的血浆水平在 PRE 的 4 小时增加，在 POST 期间 AVA 组显著高于 C 组。可溶性血管细胞粘附分子-1（sVCAM-1）和单核细胞趋化蛋白-1（MCP-1）含量在 PRE 时的 0 和 24 小时以及 POST 时均增加，但 sVCAM-1 在 POST 时的含量低于 C 组（P<0.05），MCP-1 水平在 POST 的 24、48 和 72 小时低于静息水平（P<0.05）。DR 增加了所有 POST-DR 时间点的肌肉疼痛（P<0.01），但 oat 补充在 POST 的 48 和 72 小时缓解了疼痛（P<0.05）。
燕麦 AVA 补充剂减少了循环炎症细胞因子，并抑制了 DR 诱导的趋化因子和细胞粘附分子的表达。
ClinicalTrials.gov 标识符：NCT02584946。于 2015 年 10 月 23 日注册。
