Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude.
Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude.
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DOI：
10.1007/978-3-211-09469-3_37
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发表时间：
2008
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影响因子：
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通讯作者：
S. Hu;R. Hu;F. Li;Z. Liu;Y. Xia;G. Cui;H. Feng
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文献类型：
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作者：
S. Hu;R. Hu;F. Li;Z. Liu;Y. Xia;G. Cui;H. Feng
研究背景高压氧（hyperbaricoxygen，HBO）预处理可减轻缺血性和出血性脑损伤。本研究探讨高压氧预处理对高原创伤性脑损伤（TBI）的影响，并探讨基质金属蛋白酶-9（MMP-9）在这种保护中的作用。方法大鼠随机分为高压氧预处理组（HBOP; n=13）、高原组（HA; n=13）和高原假手术组（HASO; n=13）。除HASO组外，其余各组均采用重物坠落致伤。HBOP大鼠接受5次HBO预处理（2.5ATA，100%氧，每天1h），然后在0.6ATA的低压舱（模拟海拔4000 m的压力）中保持3天。HA大鼠接受对照预处理（1ATA，室内空气，每天1h），然后进行与HBOP组相同的程序。HASO大鼠只进行颅骨切开而不进行脑损伤。结果HBOP组神经功能评分（0.71 ± 0.49）优于HA组（1.5 7 ± 0.5 3; p<0.0 5）;高压氧预处理可显著降低脑含水量（86.24 ± 0.52vs.84.60 ± 0.37;p< 0.01）。光镜下HA组脑组织形态结构明显减少，HBOP组脑组织病理损伤明显减轻。HBO预处理组MMP-9阳性细胞数为92.25 ± 8.85vs.74.42 ± 6.27，与HA组比较差异有显著性（P<0.01）。MMP-9表达的降低可能与HBO预处理对脑组织的保护作用有关。
BackgroundRecent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection.MethodsRats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n=13), high-altitude group (HA; n=13), and high-altitude sham operation group (HASO; n=13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000 m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by H&E staining and immunohistochemistry.ResultsNeurological outcome in HBOP group (0.71 ± 0.49) was better than HA group (1.57 ± 0.53; p<0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 ± 0.52 vs. 84.60 ± 0.37;p< 0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 ± 8.85 vs. 74.42 ± 6.27;p<0.01).ConclusionsHBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO precon-ditioning-induced protection of brain tissue against TBI.