The 2nd Department of Intensive Care Unit, the Second Hospital of Anhui Medical University, Hefei, Anhui Province 230601, China; Department of Intensive Care Unit, West Branch of the First Affiliated Hospital of University of Science and Technology of China, Hefei, Anhui Province 230031, China; The Laboratory of Cardiopulmonary Resuscitation and Critical Care Medicine, the Second Hospital of Anhui Medical University, Hefei, Anhui Province 230601, China.
Key Laboratory of Anesthesiology and Perioperative Medicine of Anhui Higher Education Institutes, Anhui Medical University, Hefei, Anhui Province 230601, China; Department of Anesthesiology and Perioperative Medicine, the Second Hospital of Anhui Medical University, Hefei, Anhui Province 230601, China.
Brain Res Bull. 2023 Mar;194:128-138. doi: 10.1016/j.brainresbull.2023.01.012. Epub 2023 Jan 29.
Acetaldehyde dehydrogenase 2 (ALDH2) plays an important part in neuroprotection; however, its effect on sepsis-induced brain injury is nuclear. Our aim is to investigate the potential effect and mechanism of ALDH2 in this condition.
We established an animal model using cecal ligation and perforation (CLP). Twenty-four rats were divided into sham group (n = 6), CLP group (n = 6), CLP + Alda-1 group (n = 6) and CLP + Cyanamide (CYA) group (n = 6). Vital signs were monitored, and arterial blood gas analysis, hippocampal histological staining and ALDH2 activity analysis were conducted. Western blot analysis and enzyme-linked immunosorbent assays were also carried out. Lipopolysaccharide (LPS)-treated HT22 cells were employed as an in vitro model of sepsis-induced brain injury, with and without pretreatment with Alda-1 or CYA, to further examine the potential mechanisms. Real-time quantitative polymerase chain reaction and western blot were used to determine the levels of pyrin domain-containing 3 (NLRP3) inflammasome.
We found hippocampal cell injury in the CLP group (p < 0.05), with decreased ALDH2 activity (p < 0.05) and suspected overexpression of NLRP3/caspase-1 axis (p < 0.05). In the group pretreated with Alda-1, there were increased ALDH2 activity (p < 0.05), decreased hippocampal cell damage (p < 0.05), and reduced protein levels of NLRP3, apoptosis-associated speck like protein containing a caspase recruitment domain (ASC), cleaved caspase-1 and Gasdermin D (GSDMD) (p < 0.05). The levels of interleukin 18 (IL-18) and interleukin 1β (IL-1β) were also reduced (p < 0.05). In the group pretreated with CYA, ALDH2 activity was further declined, the cell injury grade increased, and the elevated levels of pyroptosis-related proteins aggravated (p < 0.05). LPS treatment decreased the cell viability and ALDH2 activity of the HT22 cells (p < 0.05), along with increased mRNA levels of the NLRP3 inflammasome, as well as IL-1β and IL-18 (p < 0.05). Western blot further revealed elevated levels of NLRP3, ASC, cleaved caspase-1 and GSDMD (p < 0.05). In the LPS+Alda-1 group, there were increased cell viability (p < 0.05), elevated ALDH2 activity (p < 0.05), and reduced levels of NLRP3 inflammasome and pyroptosis-related proteins (p < 0.05). In the CYA+LPS group, cell viability and ALDH2 activity were further declined (p < 0.05), while levels of NLRP3 /caspase-1 axis were increased (p < 0.05).
The activation of ALDH2 can attenuate sepsis-induced brain injury, hypothetically through regulation of the NLRP3/caspase-1 signaling pathway. Therefore, ALDH2 could potentially be considered as a new therapeutic target for the treatment of sepsis-induced brain injury.
乙醛脱氢酶 2（ALDH2）在神经保护中起着重要作用；然而，其在脓毒症诱导的脑损伤中的作用尚不清楚。本研究旨在探讨 ALDH2 在这种情况下的潜在作用和机制。
我们使用盲肠结扎穿孔（CLP）建立了动物模型。将 24 只大鼠分为假手术组（n=6）、CLP 组（n=6）、CLP+Alda-1 组（n=6）和 CLP+Cyanamide（CYA）组（n=6）。监测生命体征，进行动脉血气分析、海马组织学染色和 ALDH2 活性分析。还进行了 Western blot 分析和酶联免疫吸附测定。使用脂多糖（LPS）处理的 HT22 细胞作为脓毒症诱导的脑损伤的体外模型，用 Alda-1 或 CYA 预处理，进一步研究潜在机制。实时定量聚合酶链反应和 Western blot 用于确定吡嗪结构域包含 3（NLRP3）炎性小体的水平。
我们发现 CLP 组海马细胞损伤（p<0.05），ALDH2 活性降低（p<0.05），疑似 NLRP3/caspase-1 轴过度表达（p<0.05）。在 Alda-1 预处理组中，ALDH2 活性增加（p<0.05），海马细胞损伤减少（p<0.05），NLRP3、凋亡相关斑点样蛋白含有半胱氨酸天冬氨酸蛋白酶募集域（ASC）、切割的 caspase-1 和 Gasdermin D（GSDMD）的蛋白水平降低（p<0.05）。白细胞介素 18（IL-18）和白细胞介素 1β（IL-1β）的水平也降低（p<0.05）。在 CYA 预处理组中，ALDH2 活性进一步下降，细胞损伤程度加重，与细胞焦亡相关的蛋白水平升高（p<0.05）。LPS 处理降低 HT22 细胞的细胞活力和 ALDH2 活性（p<0.05），同时增加 NLRP3 炎性小体以及 IL-1β和 IL-18 的 mRNA 水平（p<0.05）。Western blot 进一步显示 NLRP3、ASC、切割的 caspase-1 和 GSDMD 的水平升高（p<0.05）。在 LPS+Alda-1 组中，细胞活力增加（p<0.05），ALDH2 活性增加（p<0.05），NLRP3 炎性小体和细胞焦亡相关蛋白水平降低（p<0.05）。在 CYA+LPS 组中，细胞活力和 ALDH2 活性进一步下降（p<0.05），而 NLRP3/caspase-1 轴的水平增加（p<0.05）。
ALDH2 的激活可以减轻脓毒症诱导的脑损伤，假设是通过调节 NLRP3/caspase-1 信号通路。因此，ALDH2 可能被认为是治疗脓毒症诱导的脑损伤的新治疗靶点。
