Killer Sophie C, Svendsen Ida S, Gleeson Michael
School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK,
Eur J Appl Physiol. 2015 Sep;115(9):1887-95. doi: 10.1007/s00421-015-3173-1. Epub 2015 Apr 19.
Antimicrobial proteins (AMPs) in saliva including secretory immunoglobulin A (SIgA), lactoferrin (SLac) and lysozyme (SLys) are important in host defence against oral and respiratory infections. This study investigated the effects of hydration status on saliva AMP responses to endurance exercise.
Using a randomized design, 10 healthy male participants (age 23 ± 4 years, [Formula: see text] 56.8 ± 6.5 ml/kg/min) completed 2 h cycling at 60 % [Formula: see text] in states of euhydration (EH) or dehydration (DH) induced by 24 h fluid restriction. Unstimulated saliva samples were collected before, during, immediately post-exercise and each hour for 3 h recovery.
Fluid restriction resulted in a 1.5 ± 0.5 % loss of body mass from baseline and a 4.3 ± 0.7 % loss immediately post-exercise. Pre-exercise urine osmolality was higher in DH than EH and overall, saliva flow rate was reduced in DH compared with EH (p < 0.05). Baseline SIgA secretion rates were not different between conditions; however, exercise induced a significant increase in SIgA concentration in DH (161 ± 134 to 309 ± 271 mg/L) which remained elevated throughout 3 h recovery. SLac secretion rates increased from pre- to post-exercise in both conditions which remained elevated in DH only. Overall, SLac concentrations were higher in DH than EH. Pre-exercise SLys concentrations were lower in DH compared with EH (1.6 ± 2.0 vs. 5.5 ± 6.7 mg/L). Post-exercise SLys concentrations remained elevated in DH but returned to pre-exercise levels by 1 h post-exercise in EH.
Exercise in DH caused a reduction in saliva flow rate yet induced greater secretion rates of SLac and higher concentrations of SIgA and SLys. Thus, DH does not impair saliva AMP responses to endurance exercise.
唾液中的抗菌蛋白（AMPs），包括分泌型免疫球蛋白A（SIgA）、乳铁蛋白（SLac）和溶菌酶（SLys），在宿主抵御口腔和呼吸道感染中起重要作用。本研究调查了水合状态对唾液抗菌蛋白对耐力运动反应的影响。
采用随机设计，10名健康男性参与者（年龄23±4岁，[公式：见正文]56.8±6.5 ml/kg/min）在通过24小时液体限制诱导的正常水合（EH）或脱水（DH）状态下，以60%[公式：见正文]的强度完成2小时的骑行。在运动前、运动期间、运动后立即以及恢复3小时内每小时收集未刺激的唾液样本。
液体限制导致体重较基线下降1.5±0.5%，运动后立即下降4.3±0.7%。运动前DH组的尿渗透压高于EH组，总体而言，与EH组相比，DH组的唾液流速降低（p<0.05）。不同条件下基线SIgA分泌率无差异；然而，运动导致DH组SIgA浓度显著增加（从161±134至309±271 mg/L），并在整个3小时恢复期内保持升高。两种条件下SLac分泌率从运动前到运动后均增加，仅在DH组中保持升高。总体而言，DH组的SLac浓度高于EH组。运动前DH组的SLys浓度低于EH组（1.6±2.0 vs. 5.5±6.7 mg/L）。运动后DH组的SLys浓度保持升高，但在EH组中运动后1小时恢复到运动前水平。
脱水状态下运动导致唾液流速降低，但诱导了更高的SLac分泌率以及更高浓度的SIgA和SLys。因此，脱水状态不会损害唾液抗菌蛋白对耐力运动的反应。
