Fast hyperbaric decompression after heliox saturation altered the brain proteome in rats

Better understanding of the physiological mechanisms and neurological symptoms involved in the development of decompression sickness could contribute to improvements of diving procedures. The main objective of the present study was to determine effects on the brain proteome of fast decompression (1 bar/20 s) compared to controls (1 bar/10 min) after heliox saturation diving, using rats in a model system. The protein S100B, considered a biomarker for brain injury, was not significantly different in serum samples from one week before, immediately after, and one week after the dive. Alterations in the rat brain proteome due to fast decompression were investigated using both iontrap and orbitrap LC-MS, and 967 and 1062 proteins were quantified, respectively. Based on the significantly regulated proteins in the iontrap (56) and orbitrap (128) datasets, the networks “synaptic vesicle fusion and recycling in nerve terminals” and “translation initiation” were significantly enriched in a system biological database analysis (Metacore). Ribosomal proteins (RLA2, RS10) and the proteins hippocalcin-like protein 4 and proteasome subunit beta type-7 were significantly upregulated in both datasets. The heat shock protein 105 kDa, Rho-associated protein kinase 2 and Dynamin-1 were significantly downregulated in both datasets. Another main effect of hyperbaric fast decompression in our experiment is inhibition of endocytosis and stimulation of exocytosis of vesicles in the presynaptic nerve terminal. In addition, fast decompression affected several proteins taking parts in these two main mechanisms of synaptic strength, especially alteration in CDK5/calcineurin are associated with a broad range of neurological disorders. In summary, fast decompression after heliox saturation affected the brain proteome in a rat model for diving, potentially disturbing protein homeostasis, e.g. in synaptic vesicles, and destabilizing cytoskeletal components. Data are available via ProteomeXchange with identifier PXD006349

加深对减压病发生过程中涉及的生理机制与神经症状的理解，有助于优化潜水作业流程。本研究以大鼠为模型体系，旨在探究氦氧饱和潜水后，快速减压（1 bar/20 s）相较于对照减压（1 bar/10 min）对大脑蛋白质组的影响。被视为脑损伤生物标志物的S100B蛋白，在潜水前1周、潜水后即刻及潜水后1周的血清样本中未呈现显著差异。本研究采用离子阱（iontrap）与轨道阱（orbitrap）液相色谱-质谱联用（LC-MS）技术，探究快速减压所致大鼠大脑蛋白质组的变化，分别定量到967和1062种蛋白质。基于离子阱数据集（56个差异调控蛋白）与轨道阱数据集（128个差异调控蛋白）中的显著差异蛋白，通过系统生物学数据库Metacore分析发现，“神经末梢突触囊泡融合与循环”及“翻译起始”这两个通路显著富集。在两个数据集中共鉴定到显著上调的蛋白包括核糖体蛋白（RLA2、RS10）、海马钙结合蛋白样蛋白4（hippocalcin-like protein 4）以及蛋白酶体β亚基7型；而热休克蛋白105 kDa、Rho相关蛋白激酶2（Rho-associated protein kinase 2）以及发动蛋白1（Dynamin-1）则在两个数据集中共显著下调。本实验中高压快速减压的另一主要效应是抑制突触前神经末梢的囊泡内吞作用，并促进其囊泡胞吐作用。此外，快速减压影响了参与突触强度这两大核心机制的多种蛋白，其中CDK5/钙调神经磷酸酶（calcineurin）的异常与多种神经疾病密切相关。综上，氦氧饱和潜水后的快速减压会改变大鼠潜水模型的大脑蛋白质组，可能干扰突触囊泡等区域的蛋白质稳态，并破坏细胞骨架组分。本研究数据已通过蛋白质组交换数据库（ProteomeXchange）公开，编号为PXD006349。