高压氧对重症中暑大鼠认知障碍的保护作用

目的研究高压氧（HBO）治疗对大鼠重症中暑脑损伤模型认知功能障碍的保护作用。 方法将60只雄性SD大鼠随机分为空白对照组（Control组，10只）、重症中暑组（HS组，10只）、重症中暑＋高压氧治疗组（HS＋HBO组，10只）、重症中暑＋高压空气对照组（HS＋HBA组，10只）、高压氧对照组（HBO组，10只）、高压空气对照组（HBA组，10只），将HS组、HS＋HBO组、HS＋HBA组大鼠持续暴露于40℃热舱中，当核心体温达到42℃后取出复温，HS＋HBO组与HS＋HBA组复温30 min后分别给予HBO（2.5ATA，60 min）或高压空气（2.5ATA，60 min）处理，通过Morris水迷宫实验评估认知功能（航行距离和时间、目标象限航行时间百分比和通过次数），并检测各组大脑海马组织病理、神经功能评分及病死率变化。 结果HS组大鼠水迷宫寻找平台潜伏期较Control组明显延长［（45.84±0.13）s vs （22.16±1.40）s，t=-2.4，P=0.04］，寻找平台航行距离延长［（815.70±36.80）cm vs （177.71±21.00）cm，t=-3.3，P=0.01］，通过次数［（1.90±0.16）次 vs （5.80±0.20）次，t=3.7，P=0.04］和目标象限航行时间百分比［（32.12±0.19）% vs （57.12±1.60）%，t=2.8，P=0.02］明显减少；HBO治疗缩短了寻找平台的潜伏期［（30.21±1.50）s］与航行距离［（165.58±7.04）cm］，增加了穿越次数［（4.40±0.18）次］和目标象限航行时间百分比［（41.87±1.17）%］；HBO改善了HS组大鼠海马组织病理损伤程度，降低了中暑后2 h、24 h神经功能评分［2 h：（7.70±0.42）分 vs （9.60±0.31）分，t=6.3，P=0.00；24 h：（3.90±0.20）分 vs （5.60±0.23）分，t=2.4，P=0.02］及病死率（20.0% vs 40.0%，P=0.08），HS＋HBA组较HS组无明显改变，HBO组、HBA组较Control组无明显改变。 结论HBO可能是通过减轻重症中暑对海马的损伤来改善大鼠重症中暑模型的认知功能障碍。

Protective effect of hyperbaric oxygen to thecognitive impairment caused by severe heatstroke in a rat model

ObjectiveTo investigate the protective effect of hyperbaric oxygen (HBO) on the cognitive impairment caused by severe heat stroke (HS). Methods60 male Sprague-Dawley rats were randomly divided to the control group, the HS group, the HBO group, the hyperbaric air (HBA) group, the HS+ HBO group and HS+ HBA group, each group had 10 rats. The rats were exposed to 40℃ heat chamber. When the core temperature reached 42℃, they were taken out as the onset of severe heatstroke. Rats in HS+ HBO and HBO groups were placed in the hyperbaric chambers with pure oxygen at 2.5ATA for 60 min while HS+ HBA and HBA rats were placed with air. Cognitive functions were tested by Morris water maze. The pathology of hippocampus, neurological function scoreand the mortality rates were evaluated among different groups. ResultsThe escape latency time and distance was significantly increased in the HS group compared with control group (45.84±0.13) s vs (22.16±1.40) s, t=-2.4, P=0.04; (815.7±36.8) cm vs (177.71±21.00) cm, t=-3.3, P=0.01]; the number of platform-crossing and the activity time of target quadrant was significantly reduced in the HS group compared with control (1.90±0.16) times vs (5.80±0.20) times, t=3.7, P=0.04; (32.12±0.19)% vs (57.12±1.60)%, t=2.8, P=0.020]. HBO reduced the escape latency time (30.21±1.50) s] and distance (165.58±7.04) cm] significantly, and HBO increased the number of platform-crossing (4.40±0.18) times] and the activity time of target quadrant (41.87±1.17)%] significantly. HBO alleviated the injury to hippocampus in pathological observation, reduced the mNSS scores 2 and 24 hours after HS 2 h: (7.70±0.42) scores vs (9.60±0.31) scores, t=6.3, P=0.00; 24 h: (3.90±0.20) scores vs (5.60±0.23) scores, t=2.4, P=0.02] and the mortality rate of HS (20.0% vs 40.0%, P=0.08). There was no significant change in HS+ HBA group compared with HS group, and there was no significant changes in HBO group and HBA group compared with Control group. ConclusionHBO may alleviate the cognitive impairment which caused by HS through the protective effects of hippocampus.