METHODS: The experiment consisted of two parts. In the first part, C57BL/6 J male mice were divided into five groups using a random number table method: control group, sham surgery group, sepsis group, HBOT + sepsis group, and HBOT + sham surgery group. In the subsequent part, C57BL/6 J male mice were divided into four groups: sepsis group, HBOT + sepsis group, HIF-1α + HBOT + sepsis group, and HIF-1α + sepsis group. Sepsis was induced via cecal ligation and puncture (CLP). Hyperbaric oxygen therapy was administered at 1 h and 4 h post-CLP. After 24 h, blood and hippocampal tissue were collected for cytokine measurements. HIF-1α, TNF-α, IL-1β, and IL-6 expression were assessed via ELISA and western blotting. Microglial expression was determined by immunofluorescence. Blood-brain barrier permeability was quantified using Evans Blue. Barnes maze and fear conditioning were conducted 14 days post-CLP to evaluate learning and memory.
RESULTS: Our findings reveal that CLP-induced hippocampus-dependent cognitive deficits coincided with elevated HIF-1α and increased TNF-α, IL-1β, and IL-6 levels in both blood and hippocampus. Observable activation of microglial cells in the hippocampus and increased blood-brain barrier (BBB) permeability were also evident. HBOT mitigated HIF-1α, TNF-α, IL-1β, and IL-6 levels, attenuated microglial activation in the hippocampus, and significantly improved learning and memory deficits in CLP-exposed mice. Additionally, these outcomes were corroborated by injecting a lentivirus that overexpressed HIF-1α into the hippocampal region of the mice.
CONCLUSIONS: HIF-1α escalation induced peripheral and central inflammatory factors, promoting microglial activation, BBB impairment, and cognitive dysfunction. However, HBOT ameliorated these effects by reducing HIF-1α levels in Sepsis-Associated Encephalopathy.
方法:实验由两部分组成。在第一部分,采用随机数字表法将C57BL/6J雄性小鼠分为5组:对照组,假手术组,脓毒症组,HBOT+脓毒症组,HBOT+假手术组。在随后的部分,将C57BL/6J雄性小鼠分为四组:脓毒症组、HBOT+脓毒症组,HIF-1α+HBOT+脓毒症组,和HIF-1α+脓毒症组。通过盲肠结扎和穿孔(CLP)诱导脓毒症。高压氧治疗在CLP后1小时和4小时进行。24小时后,收集血液和海马组织进行细胞因子检测.HIF-1α,TNF-α,IL-1β,通过ELISA和蛋白质印迹法评估IL-6的表达。通过免疫荧光测定小胶质细胞的表达。使用伊文思蓝定量血脑屏障通透性。CLP后14天进行Barnes迷宫和恐惧调节以评估学习和记忆。
结果:我们的发现表明,CLP诱导的海马依赖性认知缺陷与升高的HIF-1α和升高的TNF-α相一致,IL-1β,血液和海马中的IL-6水平。海马中可观察到的小胶质细胞活化和血脑屏障(BBB)通透性增加也是明显的。HBOT减轻了HIF-1α,TNF-α,IL-1β,和IL-6水平,减弱海马中的小胶质细胞激活,并显著改善CLP暴露小鼠的学习和记忆缺陷。此外,通过向小鼠海马区注射过表达HIF-1α的慢病毒证实了这些结果.
结论:HIF-1α升高可诱导外周和中枢炎症因子升高,促进小胶质细胞激活,BBB受损,和认知功能障碍。然而,HBOT通过降低脓毒症相关脑病中的HIF-1α水平来改善这些作用。