Results With the prolonged exposure to heat , the mice exhibited swollen and disorderly arranged neurons , shrunken cells , and contracted and deeply stained nuclei , with significantly higher scores on nerve pathological injury evaluation at 6, 12, and 24 h (2.78 ± 0.71, 3.21 ±0.56, and 3.36 ±0.63) than the control mice (0.43 ±0.10) (P<0.05).ELISA showed remarkably elevated levels of UCH-L1 in the serum (F=147.7, P=0.05) and brain tissue (F=145.7, P=0.05) in the heat stress group as compared with the con-trol, and Western blot also revealed a markedly higher expression of UCH-L1 in the brain tissue in the former group than in the latterObjective The abnormal expression of ubiquitin C-terminal hydrolase-L1 ( UCH-L1 ) has an important role in the diagnosis and prognosis of brain damage .This study was to investigate the changes of UCH-L1 in the serum and brain tissue in the mouse model of heat stress . Methods Twelve BALB/c mice were randomly divided into a control and a heat stress group of equal number, the former placed at a temperature of (25.0 ±0.5)℃and a relative humidity of (35 ±5)%and the latter in a simulated in-cubator at (35.5 ±0.5)℃and a relative humidity of (60 ±5)%.When the rectal temperature reached 42℃, the animals were re-moved from the incubator and cooled at an ambient temperature of (25.0 ±0.5)℃and a humidity of (35 ±5)%for 0, 6, 12, and 24 h.Then the brain tissues of all the animals were harvested for HE staining , evaluation of neuronal injury under the light microscope , measurement of the UCH-L1 levels in the serum and brain tissue by ELISA , Western blot, and immunohistochemistry , respectively. (F=261.2, P=0.01).Immunohistochemistry manifested that , with the prolonged exposure to heat , the UCH-L1 expression in the brain tissue was characterized by gradually increased light brown of the neurons at staining . Conclusion Severe heatstroke causes brain injury in a time-dependent manner , and the abnormally elevated levels of UCH-L1 in the serum and brain tissue can be a marker of heatstroke-induced brain injury .%目的：泛素羧基末端水解酶-1（ubiquitin C-terminal hydrolase-L1， UCH-L1）表达异常对脑损伤的诊断及预后有一定价值。文中通过制备热打击中暑动物模型，探讨重症中暑脑组织和血清中UCH-L1水平的变化及意义。方法 BALB／c小鼠按随机数字法分为对照组和热打击组，对照组始终置于常温（25．0±0．5）℃，相对湿度（35±5）％环境下，热打击组置于仿真高温气候舱内，舱内温度（35．5±0．5）℃，相对湿度（60±5）％，记录小鼠直肠温度（Tc），当热打击小鼠Tc达42℃移置（25．0±0．5）℃、（35±5）％相对湿度环境下，复温分为0、6、12、24 h 4个时间点；分离中暑动物脑组织行HE染色，显微镜下观察并行脑组织神经元神经病理损伤评分；ELISA法检测中暑动物血清及脑组织中UCH-L1表达水平；Western blot 和免疫组化法检测中暑动物脑组织中UCH-L1表达水平。结果小鼠经热打击后，随着复温时间延长（6、12、24 h），神经元肿胀、排列紊乱，细胞皱缩，核固缩深染细胞数不断增多，神经病理损伤评分明显增高，分别为（2．78±0．71）、（3．21±0．56）和（3．36±0．63）分，与对照组的（0．43±0．10）分比较的差异有统计学意义（P均＜0．01）；ELISA检测血清和脑组织中UCH-L1水平，发现随着复温时间延长其表达增高，与对照组相比差异有统计学意义（ P＜0．05）；Western blot检测结果表明热打击后脑组织中UCH-L1表达逐渐增多，与对照组相比差异有统计学意义（P＜0．01）；免疫组化法检测发现，热打击组脑组织中UCH-L1表达逐渐增多，表现为神经元细胞质中淡棕色染色逐渐增强。结论重症中暑导致的脑损伤呈时间依赖性加重，血清及脑组织中UCH-L1表达异常增高可作为重症中暑脑损伤程度标志物。
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