Translational Neurosurgery and Neurobiology, University Hospital Aachen, RWTH Aachen, Aachen, Germany.
Department of Neurosurgery, University Hospital Aachen, RWTH Aachen, Aachen, Germany.
PLoS One. 2019 Jul 30;14(7):e0220467. doi: 10.1371/journal.pone.0220467. eCollection 2019.
Many details of the pathophysiology of subarachnoid haemorrhage (SAH) still remain unknown, making animal experiments an indispensable tool for assessment of diagnostics and therapy. For animal protection and project authorization, one needs objective measures to evaluate the severity and burden in each model. Corticosterone is described as a sensitive stress parameter reflecting the acute burden, and inflammatory markers can be used for assessment of the extent of the brain lesion. However, the brain lesion itself may activate the hypothalamic-pituitary-adrenal-axis early after SAH, as shown for ischemic stroke, probably interfering with early inflammatory processes, thus complicating the assessment of severity and burden on the basis of corticosterone and inflammation. To assess the suitability of these markers in SAH, we evaluated the courses of corticosterone, IL-6 and TNF-α up to 6h in an acute model simulating SAH in continuously anaesthetized rats, lacking the pain and stress induced impact on these parameters. Animals were randomly allocated to sham or SAH. SAH was induced by cisterna magna blood-injection, and intracranial pressure and cerebral blood flow were measured under continuous isoflurane/fentanyl anaesthesia. Withdrawn at predetermined time points, blood was analysed by commercial ELISA kits. After 6h the brain was removed for western blot analysis of IL-6 and TNF-α. Serum corticosterone levels were low with no significant difference between sham and SAH. No activation of the HPA-axis was detectable, rendering corticosterone a potentially useful parameter for stress assessment in future chronic studies. Blood IL-6 and TNF-α increased in both groups over time, with IL-6 increasing significantly more in SAH compared to sham towards the end of the observation period. In the basal cortex, IL-6 and TNF-α increased only in SAH. The pro-inflammatory response seems to start locally in the brain, reflected by an increase in peripheral blood. An additional surgery-induced systemic inflammatory response should be considered.
蛛网膜下腔出血（SAH）的许多病理生理学细节仍然未知，这使得动物实验成为评估诊断和治疗的不可或缺的工具。为了动物保护和项目授权，人们需要客观的措施来评估每个模型的严重程度和负担。皮质酮被描述为反映急性负担的敏感应激参数，而炎症标志物可用于评估脑损伤的程度。然而，正如缺血性中风所显示的那样，脑损伤本身可能会在 SAH 后早期激活下丘脑-垂体-肾上腺轴，可能会干扰早期的炎症过程，从而使基于皮质酮和炎症来评估严重程度和负担变得复杂。为了评估这些标志物在 SAH 中的适用性，我们在模拟 SAH 的急性模型中连续麻醉大鼠中评估了皮质酮、IL-6 和 TNF-α 的过程，该模型缺乏对这些参数产生疼痛和应激的影响。动物随机分配到假手术或 SAH 组。通过枕骨大孔血注入诱导 SAH，并在持续异氟烷/芬太尼麻醉下测量颅内压和脑血流。在预定时间点抽取血液，通过商业 ELISA 试剂盒进行分析。6 小时后取出大脑，用于 Western blot 分析 IL-6 和 TNF-α。血清皮质酮水平较低，假手术和 SAH 之间无显著差异。未检测到 HPA 轴的激活，这使得皮质酮成为未来慢性研究中应激评估的潜在有用参数。两组的血液 IL-6 和 TNF-α随时间增加，SAH 组的 IL-6 比假手术组在观察期结束时显著增加。在基底皮质中，仅在 SAH 中增加了 IL-6 和 TNF-α。炎症反应似乎首先在大脑局部开始，外周血中增加反映了这一点。应考虑额外的手术引起的全身炎症反应。
