Snipe Rhiannon M J, Khoo Anthony, Kitic Cecilia M, Gibson Peter R, Costa Ricardo J S
Department of Nutrition Dietetics & Food, Monash University, Notting Hill, Australia.
School of Health Sciences, University of Tasmania, Launceston, Australia.
Int J Sports Med. 2018 Feb 7. doi: 10.1055/s-0043-122742.
The study aimed to determine the effects of mild exertional heat stress on intestinal injury, permeability, gastrointestinal symptoms, and systemic endotoxin and cytokine responses. Ten endurance runners completed 2 h of running at 60% V̇O in warm (WARM: 30°C) and temperate (TEMP: 22°C) ambient conditions. Rectal temperature (T) and gastrointestinal symptoms were recorded every 10 min during exercise. Blood samples were collected pre- and post-exercise, and during recovery to determine plasma intestinal fatty acid-binding protein (I-FABP) and cortisol concentrations, and systemic endotoxin and inflammatory cytokine profiles. Urinary lactulose:L-rhamnose ratio (L/R) was used to measure small intestine permeability. Compared with TEMP, WARM significantly increased T from 50 min onwards (38.1±0.3°C vs. 38.4±0.5°C, respectively; p<0.01), gastrointestinal symptoms (p=0.017), post-exercise plasma cortisol (26% vs. 59%, respectively; p<0.001) and I-FABP (127% vs. 184%, respectively; p<0.001) concentrations. Circulatory anti-endotoxin antibodies increased post-exercise (p<0.001) on WARM (20%) and TEMP (28%). No differences were observed for plasma endotoxin concentration (6% vs. 5% increase, respectively) or small intestine permeability (L/R 0.026±0.010 and 0.025±0.015, respectively). Both pro- and anti-inflammatory cytokines increased post-exercise, with inflammatory response cytokines TNF-α (p=0.015) and IL-8 (p=0.044), and compensatory anti-inflammatory cytokines IL-10 (p=0.065), and IL-1ra higher on WARM than TEMP. Findings suggest that exposure to warm ambient conditions during prolonged submaximal running induces transient intestinal epithelial injury, increases gastrointestinal symptoms, and promotes greater perturbations to the systemic cytokine profile compared to running in temperate conditions.
该研究旨在确定轻度运动性热应激对肠道损伤、通透性、胃肠道症状以及全身内毒素和细胞因子反应的影响。10名耐力跑者在温暖（WARM：30°C）和温带（TEMP：22°C）环境条件下，以60%的最大摄氧量进行了2小时的跑步。运动期间每10分钟记录一次直肠温度（T）和胃肠道症状。在运动前、运动后以及恢复期间采集血样，以测定血浆肠脂肪酸结合蛋白（I-FABP）和皮质醇浓度，以及全身内毒素和炎性细胞因子谱。尿乳果糖：L-鼠李糖比率（L/R）用于测量小肠通透性。与TEMP相比，WARM从50分钟起显著提高了T（分别为38.1±0.3°C和38.4±0.5°C；p<0.01）、胃肠道症状（p=0.017）、运动后血浆皮质醇（分别为26%和59%；p<0.001）和I-FABP（分别为127%和184%；p<0.001）浓度。循环抗内毒素抗体在运动后增加（p<0.001），WARM组增加了20%，TEMP组增加了28%。血浆内毒素浓度（分别增加6%和5%）或小肠通透性（L/R分别为0.（此处原文可能有误，推测为0.026±0.010和0.025±0.015））未观察到差异。促炎和抗炎细胞因子在运动后均增加，与TEMP相比，WARM组的炎性反应细胞因子TNF-α（p=（此处原文可能有误，推测为0.015））和IL-8（p=0.044）以及代偿性抗炎细胞因子IL-10（p=0.065）和IL-1ra更高。研究结果表明，与在温带条件下跑步相比，长时间次最大强度跑步期间暴露于温暖环境会导致短暂的肠上皮损伤，增加胃肠道症状，并使全身细胞因子谱受到更大干扰。
