高压氧对快速减压致中枢神经损伤诱发神经元凋亡的效用

目的研究成年大鼠快速减压致中枢神经系统（CNS）损伤后神经组织细胞凋亡的变化及高压氧（HBO）暴露的效用。方法SD大鼠40只，按随机数字法分为10组，每组4只，即正常对照组、安全减压组、快速减压4个组（1．0MPa暴露5．5min后快速（50S）减至常压后6，24，48，72h组）、HBO4个组（快速减压后5h给予0．25MPa HBO暴露60min）。大鼠均分别于快速减压后6，24，48和72h同期取大脑，用原位末端TUNEL法标记凋亡细胞，光学显微镜下观察形态学改变和高倍镜计数阳性细胞计算凋亡指数。结果正常对照组和安全减压组未标记出TUNEL阳性细胞；快速减压致伤动物6h组CNS组织内仅见少量散在阳性细胞；24h组凋亡指数较6h组增加（P〈0．01）；48和72h组明显增加，达到高峰（P〈0．01）；TUNEL阳性凋亡细胞主要为神经元细胞。HBO暴露组24h组神经元凋亡指数明显较快速减压组相同时间组降低（P〈0．05），48h和72h组降低更加显著（P〈0．01）。结论神经元凋亡是快速减压致CNS损伤中神经元丧失的重要形式之一：HBO暴露能够减少损伤后期的神经元凋亡，对保存神经元、改善预后起到重要作用。

The effects of hyperbaric oxygenation on central nerve cell apoptosis induced by very fast decompressing

Objective To investigate the change of neuron apoptosis in adult rats following rapid decompressing and the effect of hyperbaric oxygenation(HBO) on central nerve cell apoptosis.Methods The fast decompressing rats' models of decompression sickness were established by fast decompressing(50 s) after 1.0 MPa exposure force 5.5 min.HBO was inducted 6 h later. Brain tissues were collected at 6 h,24 h,48 h and 72 h after fast decompression.Apoptosis cells were detected by in situ end labeling TUNEL methods.Apoptosis indexs were determined by counting the TUNEL positive cells under 400 times field of vision.Results There was no TUNEL positive cell in the brain tissue of normal control and safe decompression animals.There were a few TUNEL positive cells in the brain tissue of animals sacrificed at 6 h after fast decompression,increased at 24 h(P<0.01) and peaked at 48 h and 72 h(P<0.01).According as their morphological appearance,the apoptosis cells were suggested to be neuron.The amount of neuron apoptosis in brain tissue of animals exposed to HBO sacrificed at 24 h after fast decompression was decreased significantly than that of fast decompressing group at the same time(P<0.01).The extent of decreasing was bigger in 48 h and 72 h after HBO inducted.Conclusions The neuron apoptosis was an important form of neuron loss induced by fast decompression.HBO could improve the circumstance of neuron in brain tissue suffered fast decompression-induced CNS injury,decrease the neuron apoptosis,and play an important role in protection of injured neuron.