模拟高原训练损伤小肠黏膜屏障引发NF-κB等炎症因子水平上调

Simulated Altitude Exercise Training Impaired Intestinal Mucosal Barrier and Up-regulated Inflammatory Factor Such as NF-κB

运动员在高原训练中,低氧与运动双重应激中常出现的腹泻、腹痛、食欲不振及其他消化系统紊乱,可能与小肠微观形态受损和伴随发生的细菌增殖异位及炎症有关。本研究构建SD大鼠高原训练模型,观察模拟高原训练对大鼠携氧用氧能力、小肠黏膜屏障完整性、小肠细菌量及小肠NF-κB等炎症因子表达的影响。血液细胞分析结果显示,低氧暴露和低氧训练导致大鼠红细胞数和红细胞压积显著上升。苏木精-伊红染色组织切片证实,低氧暴露导致大鼠小肠机械屏障轻微损伤,低氧训练导致大鼠小肠机械屏障严重受损。荧光原位杂交结果显示,低氧暴露导致大鼠小肠出现细菌增殖发生菌群异位,低氧训练导致增殖和异位现象加剧。蛋白质免疫印迹结果显示,NF-κB仅在低氧暴露和低氧训练组出现高表达,运动组与大鼠对照组无显著差异。逆转录聚合酶链式反应结果显示,TNF-α和IL-6作为NF-κB的下游因子,出现相似的变化趋势。以上结果表明,本研究建立的动物模型可以达到模拟高原训练的目的,高原训练导致大鼠小肠机械屏障被破坏,发生细菌增殖、细菌异位,进而引发小肠炎症因子水平上升。初步揭示了高原训练中运动员出现消化系统不适、腹泻的原因。对于通过补充有益菌的方式平衡菌群,缓解小肠损伤及炎症,解决高原训练中运动员消化系统不适的问题有待继续研究。

During altitude training, athelets are often subjected to diarrhea, abdominal pain, loss of appetite and other digestive disorders. The establishment of animal model with SD rat by simulating altitude training aims to analyze the capacity of oxygen consumption, the integrity of intestinal mucosa barrier, the number of bacteria and the expression of inflammatory cytokines. Red blood cells and hematokrit were significantly up-regulated in low oxygen sedentary group and low oxygen exercise group when compared with groups exposed to normal oxygen condition. HE staining showed that there were damages in different levels of intestinal mucosa barrier in low oxygen sedentary group and low oxygen exercise group. Results from fluorescent in situ hybridization revealed that there was more bacteriamultiplication in low oxygen sedentary group and low oxygen exercise group. Western blotting revealed that the levels of NF-KB protein in low oxygen sedentary group and low oxygen exercise group were much higher than control groups, while reverse transcription-polymerase chain reaction （RT-PCR） revealed that the mRNA levels of TNF-a and IL-6 in low oxygen sedentary group and low oxygen exercise group were much higher than control groups. These data indicated that the animal models established in this study can be used for simulating plateau training. Simulating plateau training could aggravate level of inflammatory factor through injure intestinal mechanical barrier and multiply the bacterial translocation in rats. This study provided the preliminary evidence for digestive discomfort in high altitude.