内皮微粒在减压病血管炎性损伤中的形成机制及其作用

With the progress of the national marine strategy , the frequency and depth of human activities underwater are increasing, which put forward the higher requirements of diving medical support technology, and the prevention and treatment of decompression sickness (DCS) has become the core of the problem in diving medical support. Conventional wisdom holds that the vascular occlusion induced by intravascular bubbles due to improper decompression is the root cause of DCS, with the further research, it was discovered that extensive vascular inflammatory damage triggered by intravascular bubbles has played a key role in the development of DCS, but its mechanism is not clear. Our previous study found that circulating endothelial microparticles (EMPs) were significantly increased in DCS rats with vascular inflammatory injury. Intravenous injection with EMPs from endothelial cell culture induced by bubble perfusion induced vascular inflammatory injury in normal rats, that closely related to the p38/MAPK signaling pathway. With a broad spectrum of biological activity, EMPs represent a population of vesicles released by budding of the plasma membrane during endothelial cell activation or early apoptosis, that is likely to be the core regulatory control of vascular inflammatory injury mechanism in DCS. Our research project is intended to use vascular segment and primary endothelial cell culture from rat pulmonary artery, and establish the vitro model of bubble perfusion to simulate the injury induced by DCS bubbles. With this model, we aim to verify the biological effects of EMPs in vascular inflammatory injury of DCS and reveal the role of p38/MARK signaling pathway in the formation mechanism of EMPs. So our research will provide a new basis for elucidating the pathogenesis of DCS and explore new ideas for the prevention and treatment of DCS.

国家海洋战略不断推进，人类水下活动频次和深度不断加大，对潜水医学保障提出更高要求，其核心问题是减压病(DCS)防治。体内形成致病气泡是DCS根本原因，血管内气泡触发的广泛血管炎性损伤，在DCS的发生发展中起到了关键作用，但其机制尚不明确。我们研究发现，DCS大鼠模型中的血管炎性损伤，都伴随循环内皮微粒(EMPs)异常增加；将体外气泡灌流诱导的EMPs注入正常大鼠也可诱导相似血管炎性损伤，且与p38/MAPK信号通路密切相关。EMPs是血管内皮细胞活化或凋亡早期由胞膜出芽脱落于循环的小囊泡，很可能是DCS血管炎性损伤的核心调控环节。本课题拟利用大鼠离体血管段和原代肺动脉内皮细胞，建立体外气泡灌流模型模拟DCS气泡损伤，以验证EMPs在DCS血管炎性损伤中的生物效应，并揭示p38/MARK信号通路在EMPs形成机制中的作用，为阐明DCS发病机制提供新依据、也为探索DCS防治措施提供新思路。

国家海洋战略不断推进，人类水下活动频次和深度不断加大，对潜水医学保障提出更高要求，其核心问题是减压病(DCS)防治。体内形成致病气泡是DCS根本原因，血管内气泡触发的广泛血管炎性损伤，在DCS的发生发展中起到了关键作用，但其机制尚不明确。DCS诱发的血管炎性损伤，都伴随循环内皮微粒(EMPs)异常增加；将体外气泡灌流诱导的EMPs注入体内也可诱导相似血管炎性损伤。EMPs是血管内皮细胞(ECs)活化或凋亡早期由胞膜出芽脱落于循环的小囊泡，很可能是DCS血管炎性损伤的核心调控环节。我们推测DCS血管内致病气泡通过直接触碰或改变血液层流剪切力，导致ECs被激活或损伤，产生和释放EMPs并进一步诱发血管炎症损伤级联放大效应。为观察DCS气泡诱导的EMPs在血管炎性损伤中的确切效应，我们自制微气泡生成装置模拟DCS气泡对内皮细胞的刺激作用，检测气泡刺激后培养液中EMPs生成数量的情况，判断血管内皮损伤的程度；在细胞及动物水平分别观察气泡刺激诱导的EMPs对血管内皮的损伤效应，并进一步探索气泡诱导EMPs产生的分子机制，寻找其中的关键信号分子；针对DCS致病的根本原因，即血管内致病气泡，寻找促进气体交换、减少气泡生成的方法，为DCS的防治寻找新的非加压治疗手段。我们的研究发现，气泡刺激可显著促进EMPs的产生与释放，而且气泡诱导的EMPs可进一步促进血管功能障碍及炎性损伤；气泡刺激血管内皮后通过触发胞内钙离子增加激活Rho/ROCK通路，并引起细胞膜骨架蛋白共定位减少、骨架蛋白重构，同时抑制翻转酶Flippase活性导致磷脂酰丝氨酸外露增加，促进EMPs的产生与释放；雾化吸入Surfactant可通过抑制肺内炎症反应、改善肺功能、促进惰性气体排出明显减少血管内气泡生成，并辅以抗氧化及保护内皮作用来预防DCS的发生。以上结论为阐明DCS发病机制提供新依据、也为探索DCS防治措施提供新思路。