高血糖促单核/巨噬细胞极化漂移在脊髓缺血再灌注损伤中的作用和机制研究

Spinal cord ischemia-reperfusion injury (SCIRI) and the following paralysis is a central issue of perioperative organ protection for the clinicians. The incidence of hyperglycemia is a common phenomenon in patients undergoing SCIRI-related surgery. However, the effect and mechanism of hyperglycemia on SCIRI, and its appropriate intervene time in clinic is unclear. Our preliminary experiments showed that hyperglycemia further reduced the motor function scores in mice after SCIRI, and impaired polarization of monocytes/macrophages(MDMs) to a protective anti-inflammatory phenotype during SCIRI. Therefore, the present study speculates that the skewing of macrophage polarization could be an important mechanism for hyperglycemia to worsen SCIRI. .To verify this hypothesis, we will establish GFP bone marrow chimeric mice and observe the influence of hyperglycemia on the process of SCIRI and MDMs subtypes skewing during SCIRI using flow cytometry and immunocytochemistry. We will also inject insulin into the hyperglycemic mice at several time points after injury to identify the possible time window in which glycemic control can improve functional outcome. The deletion of bone marrow–derived MDMs by clodronate-filled liposomes will be performed to demonstrate the role of MDMs in the course of SCIRI worsened by hyperglycemia. Furthermore, in order to explore the role of TLR4/JNK signaling in MDMs polarization alteration induced by hyperglycemia, we will utilize primary MDMs isolated from patients receiving ascending aorta and total arch replacement surgery..Conducting the present project would shed light on the mechanism of endogenous nerve repair after SCIRI from the perspective of macrophage phenotype modulation, and enlighten the enrichment of clinical management strategy in SCIRI-related surgeries by clarifying the effect and mechanism of hyperglycemia on SCIRI process and its possible time window for glucose control therapy.

脊髓缺血再灌注损伤(SCIRI)是围术期脏器保护领域的难题和热点。高血糖在SCIRI手术中发生率高，但其干预时机、对SCIRI影响及机制尚不清楚。预实验发现高血糖使SCIRI小鼠运动评分下降；SCIRI后浸润至脊髓的循环来源单核/巨噬细胞(MDMs)向保护性抗炎型偏移，而高血糖促使MDMs向促炎型转化，故推测这可能是高血糖加重SCIRI的重要机制。为此，本课题采用GFP骨髓嵌合体小鼠观察高血糖对SCIRI进程和循环来源MDMs亚型偏移的影响，以及降血糖有效时机；清除循环MDMs明确其在高血糖加重SCIRI中的作用。在细胞水平，利用夹层患者外周血MDMs探讨TLR4/JNK信号在高糖诱导MDMs表型转化中的作用。本研究探讨了高血糖对SCIRI影响、机制以及干预有效“时间窗”，对丰富SCIRI临床管理策略有重要启示；此外，设计基于循环来源MDMs极化漂移的调控策略也有望成为脊髓保护治疗的新思路

本课题探讨高血糖在主动脉夹层手术导致的脊髓缺血再灌注损伤对单核/巨噬细胞极化的影响和作用。本课题研究取得以下成果：1）明确了小胶质细胞和巨噬细胞在脊髓缺血再灌注损伤后随时间演变的差异性极化动态改变和作用；2）揭示了持续高糖促进外周单核细胞浸润至脊髓增加，浸润至脊髓的单核/巨噬细胞促进了糖尿病神经病变症状（病理性疼痛症状）；3）发现了主动脉夹层CD4+ T细胞耗竭，其下降水平和患者预后密切相关，而铁死亡可能是导致CD4+ T 细胞耗竭的重要原因；4）发现术中高血糖是主动脉夹层手术患者预后不良的独立危险因素。在本课题资助下，以第一或通讯作者（含共同）发表论著4篇，其中JCR1区3篇，JCR2区1篇；共同作者4篇。指导学生两次获得省级中青年优秀竞赛一等奖。本课题的实施为主动脉夹层免疫细胞在器官损伤中的作用提供了新的认识，强调了围术期免疫调控的重要性，具有一定的临床意义。