New determinants for casual peripheral mechanism of neurogenic lung edema in subarachnoid hemorrhage due to ischemic degeneration of vagal nerve, kidney and lung circuitry. Experimental study

Abstract Purpose: To evaluate whether there is a relationship between renal artery vasospasm related low glomerular density or degeneration and neurogenic lung edema (NLE) following subarachnoid hemorrhage. Methods: This study was conducted on 26 rabbits. A control group was formed of five animals, a SHAM group of 5 to which saline and a study group (n=16) injected with homologous blood into the sylvian cisterna. Numbers of degenerated axons of renal branches of vagal nerves, atrophic glomerulus numbers and NLE scores were recorded. Results: Important vagal degeneration, severe renal artery vasospasm, intrarenal hemorrhage and glomerular atrophy observed in high score NLE detected animals. The mean degenerated axon density of vagal nerves (n/mm2), atrophic glomerulus density (n/mm3) and NLE scores of control, SHAM and study groups were estimated as 2.40±1.82, 2.20±1.30, 1.80±1.10, 8.00±2.24, 8.80±2.39, 4.40±1.14 and 154.38±13.61, 34.69±2.68 and 12.19±1.97 consecutively. Degenerated vagal axon, atrophic glomerulus and NLE scores are higher in study group than other groups and the differences are statistically meaningful (p<0.001). Conclusion: Vagal complex degeneration based glomerular atrophy have important roles on NLE following SAH which has not been extensively mentioned in the literature.

摘要 目的：本研究旨在探讨蛛网膜下腔出血（subarachnoid hemorrhage, SAH）后，肾动脉痉挛相关的肾小球密度降低或变性与神经源性肺水肿（neurogenic lung edema, NLE）之间是否存在关联。方法：本研究共纳入26只家兔，设置3组实验：对照组（5只）、假手术（SHAM）组（5只，仅给予生理盐水注射）以及研究组（n=16，向外侧裂池注射同源血液）。记录迷走神经肾支的变性轴突数量、萎缩肾小球数量以及NLE评分。结果：在NLE评分较高的受试动物中，可见显著的迷走神经变性、严重肾动脉痉挛、肾内出血及肾小球萎缩。对照组、假手术组与研究组的迷走神经变性轴突密度（单位：个/mm²）、萎缩肾小球密度（单位：个/mm³）及NLE评分依次为：2.40±1.82、2.20±1.30、1.80±1.10；8.00±2.24、8.80±2.39、4.40±1.14；154.38±13.61、34.69±2.68、12.19±1.97。研究组的迷走神经变性轴突密度、萎缩肾小球密度及NLE评分均高于其余两组，且差异具有统计学显著性（p<0.001）。结论：由迷走神经复合体变性导致的肾小球萎缩，在蛛网膜下腔出血后神经源性肺水肿的发生中发挥重要作用，这一机制在既往文献中尚未得到广泛提及。