Abstract：
BACKGROUND: Sepsis-associated encephalopathy (SAE) presents a significant clinical challenge, associated with increased mortality and healthcare expenses. Hyperbaric oxygen therapy (HBOT), involving inhaling pure or highly concentrated oxygen under pressures exceeding one atmosphere, has demonstrated neuroprotective effects in various conditions. However, the precise mechanisms underlying its protective actions against sepsis-associated brain injury remain unclear. This study aimed to determine whether HBOT protects against SAE and to elucidate the impact of the hypoxia-inducible factor-1α (HIF-1α) signaling pathway on SAE.
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.
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.
摘要：
背景：脓毒症相关性脑病（SAE）提出了重大的临床挑战，与死亡率和医疗保健费用增加有关。高压氧治疗（HBOT），涉及在超过一个大气压的压力下吸入纯净或高浓度的氧气，在各种情况下都有神经保护作用。然而,其针对脓毒症相关性脑损伤的保护作用的确切机制尚不清楚.本研究旨在确定HBOT是否可以抵抗SAE，并阐明缺氧诱导因子-1α（HIF-1α）信号通路对SAE的影响。
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。
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。
