Institute of Cardiovascular Diseases, China Three Gorges University, Department of Cardiology, The First College of Clinical Medical Sciences, China Three Gorges University, 443000 Yichang, Hubei Province, China.
Gene. 2012 Nov 1;509(1):149-53. doi: 10.1016/j.gene.2012.07.072. Epub 2012 Aug 4.
This study aimed to explore the role of high mobility group [corrected] box 1 (HMGB1) and its receptor toll like receptor 4 (TLR4) on neutrophils in myocardial ischemia reperfusion (I/R) injury. We constructed TLR4-mutant (C3H/HeJ) and control (C3H/HeN) mouse models of myocardial I/R injury and subjected the mice to 30 min of ischemia and 6h of reperfusion. Light microscope was used to observe structural changes in the myocardium. HMGB1 levels were measured using quantitative real-time PCR and immunohistochemistry. Neutrophil accumulation, TNF-a expression and IL-8 levels were analyzed via myeloperoxidase (MPO) biochemical studies, quantitative real-time PCR and ELISA, respectively. The results demonstrated that fewer neutrophils infiltrated in the myocardium of TLR4-mutant mice after myocardial I/R and that TLR4 deficiency markedly decreased the ischemic injury caused by ischemia/reperfusion, and inhibited the expression of HMGB1, TNF-a, and IL-8, all of which were up-regulated by ischemia/reperfusion. These findings suggest that HMGB1 plays a central role in recruiting neutrophils during myocardial I/R leading to worsened myocardial I/R injury. This recruitment mechanism is possibly due to its inflammatory and chemokine functions based on the TLR4-dependent pathway.
本研究旨在探讨高迁移率族蛋白 B1（HMGB1）及其受体 Toll 样受体 4（TLR4）在中性粒细胞介导的心肌缺血再灌注（I/R）损伤中的作用。我们构建了 TLR4 突变（C3H/HeJ）和对照（C3H/HeN）小鼠心肌 I/R 损伤模型，并对小鼠进行 30 分钟缺血和 6 小时再灌注。使用光学显微镜观察心肌结构变化。采用实时定量 PCR 和免疫组织化学法检测 HMGB1 水平。通过髓过氧化物酶（MPO）生化研究、实时定量 PCR 和 ELISA 分别分析中性粒细胞浸润、TNF-α表达和 IL-8 水平。结果表明，在心肌 I/R 后 TLR4 突变小鼠心肌中浸润的中性粒细胞较少，TLR4 缺乏明显减轻缺血/再灌注引起的缺血损伤，并抑制 HMGB1、TNF-α和 IL-8 的表达，这些表达均因缺血/再灌注而上调。这些发现表明，HMGB1 在招募中性粒细胞参与心肌 I/R 中起核心作用，导致心肌 I/R 损伤加重。这种募集机制可能是基于 TLR4 依赖性途径的炎症和趋化因子功能。
