Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.
Tianjin Research Institute of Anesthesiology, Tianjin, China.
Shock. 2021 Jan 1;55(1):100-109. doi: 10.1097/SHK.0000000000001594.
Sepsis-associated encephalopathy (SAE) affects approximately one-third of septic patients, and there is a lack of effective therapeutics for SAE. Hydrogen gas is a new medical gas that exerts anti-inflammation, antioxidation, and anti-apoptotic effects and can effectively protect septic mice. Mitochondrial dysfunction, which can be improved by mitochondrial biogenesis, is a type of molecular pathology in sepsis. Peroxisome proliferator-activated receptor gamma co-activator 1α (PGC-1α), which can be inhibited by SR-18292, is the key regulatory factor of mitochondrial biogenesis. Therefore, we investigated the effects of hydrogen gas on mitochondrial function and mitochondrial biogenesis in mice with SAE and the related regulatory mechanisms. Cecal ligation and puncture was used to induce sepsis in mice. The mice with hydrogen gas therapy were exposed to 2% H2 inhalation for 1 h beginning at both 1 and 6 h after operation, and mice were also injected with a PGC-1α inhibitor, SR-18292. We recorded the 7-day survival rates of the mice and detected their cognitive function using a Y-maze test. The Nissl bodies in the CA1 region of hippocampus were observed by Nissl staining, and the apoptotic cells were observed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay staining. The mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) level, and mitochondrial respiratory chain complexes I and II were analyzed using commercial kits. The mitochondrial morphology was observed by transmission electron microscopy. The expression levels of PGC-1α, nuclear respiratory factor 2 (NRF2), and mitochondrial transcription factor A (Tfam) were detected by Western blot analysis. The present study showed that hydrogen gas therapy increased the 7-day survival rate, improved cognitive function, increased the mitochondrial function (MMP, ATP level, complex I activity) and expression of mitochondrial biogenesis parameters (PGC-1α, NRF2, Tfam). However, the injection of SR-18292 (a PGC-1α inhibitor) decreased mitochondrial function, PGC-1α activation, and expression of NRF2 and Tfam. Therefore, these results indicate that hydrogen gas alleviates sepsis-induced brain injury in mice by improving mitochondrial biogenesis through the activation of PGC-1α.
脓毒症相关性脑病（SAE）影响约三分之一的脓毒症患者，目前尚无有效的治疗方法。氢气是一种新型的医学气体，具有抗炎、抗氧化和抗凋亡作用，可有效保护脓毒症小鼠。线粒体功能障碍可通过线粒体生物发生得到改善，这是脓毒症的一种分子病理学类型。过氧化物酶体增殖物激活受体γ共激活因子 1α（PGC-1α）可被 SR-18292 抑制，是线粒体生物发生的关键调节因子。因此，我们研究了氢气对 SAE 小鼠线粒体功能和线粒体生物发生的影响及其相关调节机制。盲肠结扎穿孔法诱导小鼠脓毒症。氢气治疗组小鼠在术后 1 小时和 6 小时开始暴露于 2%氢气吸入 1 小时，同时注射 PGC-1α 抑制剂 SR-18292。记录小鼠 7 天存活率，并使用 Y 迷宫测试检测其认知功能。Nissl 染色观察海马 CA1 区尼氏体，末端脱氧核苷酸转移酶介导的 dUTP 生物素缺口末端标记染色观察凋亡细胞。采用商业试剂盒分析线粒体膜电位（MMP）、三磷酸腺苷（ATP）水平以及线粒体呼吸链复合物 I 和 II。透射电镜观察线粒体形态。Western blot 分析检测 PGC-1α、核呼吸因子 2（NRF2）和线粒体转录因子 A（Tfam）的表达水平。本研究表明，氢气治疗可提高 7 天存活率，改善认知功能，增加线粒体功能（MMP、ATP 水平、复合物 I 活性）和线粒体生物发生参数（PGC-1α、NRF2、Tfam）的表达。然而，注射 SR-18292（PGC-1α 抑制剂）可降低线粒体功能、PGC-1α 激活以及 NRF2 和 Tfam 的表达。因此，这些结果表明，氢气通过激活 PGC-1α 改善线粒体生物发生从而减轻脓毒症诱导的小鼠脑损伤。
