Chen Yu-Wen, Chen Sheng-Hsien, Chou Willy, Lo Yi-Ming, Hung Ching-Hsia, Lin Mao-Tsun
Department of Physical Therapy, China Medical University, Taichung, Taiwan.
Br J Sports Med. 2007 Sep;41(9):597-602. doi: 10.1136/bjsm.2006.033829. Epub 2007 May 11.
In the rat brain, heat-stroke-induced damage to cerebral neurons is attenuated through heat-shock-induced overexpression of heat-shock protein 72 (HSP72).
To ascertain whether progressive exercise preconditioning induces HSP72 expression in the rat brain and prevents heat-stroke-induced cerebral ischaemia and injury.
Male Wistar rats were randomly assigned to either a sedentary group or an exercise group. Those in the exercise group progressively ran on a treadmill 5 days/week, for 30-60 min/day at an intensity of 20-30 m/min for 3 weeks. The effects of heat stroke on mean arterial pressure, cerebral blood flow, brain ischaemia markers (glutamate, lactate/pyruvate ratio and nitric oxide), a cerebral injury marker (glycerol) and brain neuronal damage score in the preconditioned animals were compared with effects in unexercised controls. Heat stroke was induced by exposing urethane-anaesthetised animals to a temperature of 43 degrees C for 55 min, which caused the body temperature to reach 42 degrees C.
Three weeks of progressive exercise pretreatment induced HSP72 preconditioning in the brain and conferred significant protection against heat-stroke-induced hyperthermia, arterial hypotension, cerebral ischaemia and neuronal damage; it also prolonged survival.
Exercise for 3 weeks can improve heat tolerance as well as attenuate heat-stroke-induced cerebral ischaemia in rats. The maintenance of mean arterial pressure and cerebral blood flow at appropriate levels in the rat brain may be related to overexpression of HSP72.
在大鼠脑中，中暑诱导的脑神经元损伤可通过热休克诱导的热休克蛋白72（HSP72）过表达而减轻。
确定渐进性运动预处理是否能诱导大鼠脑内HSP72表达，并预防中暑诱导的脑缺血和损伤。
将雄性Wistar大鼠随机分为久坐组和运动组。运动组大鼠每周5天在跑步机上进行渐进性跑步，每天30 - 60分钟，速度为20 - 30米/分钟，持续3周。将预处理动物中暑对平均动脉压、脑血流量、脑缺血标志物（谷氨酸、乳酸/丙酮酸比值和一氧化氮）、脑损伤标志物（甘油）和脑神经元损伤评分的影响与未运动对照的影响进行比较。通过将乌拉坦麻醉的动物暴露于43℃温度下55分钟诱导中暑，这使得体温达到42℃。
3周的渐进性运动预处理可诱导脑内HSP72预处理，并对中暑诱导的体温过高、动脉低血压、脑缺血和神经元损伤提供显著保护；还可延长存活时间。
3周运动可提高大鼠的耐热性，并减轻中暑诱导的脑缺血。大鼠脑内平均动脉压和脑血流量维持在适当水平可能与HSP72过表达有关。
