Research and Education Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
Cell Stress Chaperones. 2012 May;17(3):375-83. doi: 10.1007/s12192-011-0313-3. Epub 2012 Jan 6.
Extracellular heat-shock protein 72 (eHsp72) expression during exercise-heat stress is suggested to increase with the level of hyperthermia attained, independent of the rate of heat storage. This study examined the influence of exercise at various intensities to elucidate this relationship, and investigated the association between eHsp72 and eHsp27. Sixteen male subjects cycled to exhaustion at 60% and 75% of maximal oxygen uptake in hot conditions (40°C, 50% RH). Core temperature, heart rate, oxidative stress, and blood lactate and glucose levels were measured to determine the predictor variables associated with eHsp expression. At exhaustion, heart rate exceeded 96% of maximum in both conditions. Core temperature reached 39.7°C in the 60% trial (58.9 min) and 39.0°C in the 75% trial (27.2 min) (P < 0.001). The rate of rise in core temperature was 2.1°C h(-1) greater in the 75% trial than in the 60% trial (P < 0.001). A significant increase and correlation was observed between eHsp72 and eHsp27 concentrations at exhaustion (P < 0.005). eHsp72 was highly correlated with the core temperature attained (60% trial) and the rate of increase in core temperature (75% trial; P < 0.05). However, no common predictor variable was associated with the expression of both eHsps. The similarity in expression of eHsp72 and eHsp27 during moderate- and high-intensity exercise may relate to the duration (i.e., core temperature attained) and intensity (i.e., rate of increase in core temperature) of exercise. Thus, the immuno-inflammatory release of eHsp72 and eHsp27 in response to exercise in the heat may be duration and intensity dependent.
细胞外热休克蛋白 72（eHsp72）在运动-热应激期间的表达被认为随着达到的高热水平而增加，而与热量储存的速度无关。本研究通过检查不同强度的运动对阐明这种关系的影响，以及研究 eHsp72 与 eHsp27 之间的关联。16 名男性受试者在炎热环境（40°C，50%相对湿度）下以最大摄氧量的 60%和 75%进行至力竭。测量核心温度、心率、氧化应激以及血液乳酸和葡萄糖水平，以确定与 eHsp 表达相关的预测变量。在力竭时，两种情况下的心率都超过最大心率的 96%。在 60%试验中，核心温度达到 39.7°C（58.9 分钟），在 75%试验中达到 39.0°C（27.2 分钟）（P<0.001）。75%试验中核心温度的上升速度比 60%试验快 2.1°C/h（P<0.001）。在力竭时，eHsp72 和 eHsp27 浓度之间观察到显著的增加和相关性（P<0.005）。eHsp72 与达到的核心温度（60%试验）和核心温度升高的速度（75%试验；P<0.05）高度相关。然而，没有共同的预测变量与两种 eHsp 的表达相关。在中高强度运动期间，eHsp72 和 eHsp27 的表达相似，可能与运动的持续时间（即达到的核心温度）和强度（即核心温度升高的速度）有关。因此，热应激下运动引起的 eHsp72 和 eHsp27 的免疫炎症释放可能与运动的持续时间和强度有关。
