Luo Wei, Miao Xuemei, Liu Tao, Xiong Yiyu, Dai Ruping, Li Hui
Department of Anesthesiology, Second Xiangya Hospital, Central South University, Changsha 410011, China.
Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2024 Dec 28;49(12):1875-1884. doi: 10.11817/j.issn.1672-7347.2024.240198.
Spinal cord ischemia-reperfusion injury (SCIRI) remains a major challenge in the field of organ protection due to the lack of effective prevention and therapeutic strategies. Hyperglycemia, a common perioperative condition, contributes to neurological injury via multiple mechanisms. However, its role and underlying mechanism in SCIRI are still unclear. This study aims to investigate the involvement of the precursor of brain-derived neurotrophic factor (proBDNF) in hyperglycemia-induced SCIRI in mice.
Eight-week-old male C57BL/6 mice were randomly assigned to a control group (Vehicle) or a diabetes mellitus (DM) group. The DM group was established using intraperitoneal injection of streptozotocin (STZ) combined with 10% sucrose water. The Vehicle group received an equal volume of 50 mmol/L sodium citrate buffer (pH 4.5). Fasting blood-glucose levels ≥11.1 mmol/L were considered successful DM modeling. Both Vehicle and DM groups underwent SCIRI modeling via descending aortic clamping, while the Sham group underwent a sham procedure without aortic occlusion. Lower limb motor function was assessed using the Basso Mouse Scale (BMS) and its subscale (sub-BMS). Locomotor activity was evaluated using an open field test. Immunohistochemistry was performed to detect changes in neuronal nuclear protein (NeuN) and proBDNF expression in spinal cord tissues. Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to measure mRNA expression of interleukin-1β (), interleukin-6 (), and tumor necrosis factor-α (). To explore the effect of proBDNF inhibition, diabetic mice were divided into groups: A DM+SCIRI+monoclonal anti-proBDNF antibody (McAb-proB) group received an intraperitoneal injection of 100 μg of McAb-proB 30 minutes before SCIRI modeling, and a DM+SCIRI+Vehicle group received an equal amount of isotype immunoglobulin G. BMS and sub-BMS scores were recorded, and the gene expression of inflammatory cytokines mentioned above were evaluated.
Compared with the Vehicle+SCIRI group, the DM+SCIRI group showed significantly reduced BMS and sub-BMS scores, decreased NeuN expression, shorter total movement distance, slower locomotion, increased proBDNF expression, and elevated , , and mRNA levels (all <0.05 or <0.01). Compared with the DM+SCIRI+Vehicle group, the DM+SCIRI+McAb-proB group exhibited significantly improved BMS and sub-BMS scores and decreased mRNA expression of , , and (all <0.05 or <0.01).
Hyperglycemia exacerbates neural injury and inflammatory response in SCIRI through upregulation of proBDNF expression, delaying motor functional recovery. Antagonizing proBDNF expression can alleviate neurological damage and promote functional recovery in diabetic mice after SCIRI.
由于缺乏有效的预防和治疗策略，脊髓缺血再灌注损伤（SCIRI）仍是器官保护领域的一项重大挑战。高血糖是一种常见的围手术期状况，可通过多种机制导致神经损伤。然而，其在SCIRI中的作用及潜在机制仍不清楚。本研究旨在探讨脑源性神经营养因子前体（proBDNF）在高血糖诱导的小鼠SCIRI中的作用。
将8周龄雄性C57BL/6小鼠随机分为对照组（溶媒组）或糖尿病（DM）组。DM组通过腹腔注射链脲佐菌素（STZ）并给予10%蔗糖水建立。溶媒组接受等量的50 mmol/L柠檬酸钠缓冲液（pH 4.5）。空腹血糖水平≥11.1 mmol/L被认为糖尿病建模成功。溶媒组和DM组均通过降主动脉夹闭进行SCIRI建模，而假手术组进行无主动脉阻断的假手术。使用Basso小鼠评分量表（BMS）及其子量表（sub - BMS）评估下肢运动功能。使用旷场试验评估运动活性。进行免疫组织化学检测脊髓组织中神经元核蛋白（NeuN）和proBDNF表达的变化。使用实时逆转录聚合酶链反应（RT - PCR）测量白细胞介素 - 1β（IL - 1β）、白细胞介素 - 6（IL - 6）和肿瘤坏死因子 - α（TNF - α）的mRNA表达。为探讨proBDNF抑制的作用，将糖尿病小鼠分为两组：DM + SCIRI + 抗proBDNF单克隆抗体（McAb - proB）组在SCIRI建模前30分钟腹腔注射100 μg McAb - proB，DM + SCIRI + 溶媒组接受等量的同型免疫球蛋白G。记录BMS和sub - BMS评分，并评估上述炎性细胞因子的基因表达。
与溶媒 + SCIRI组相比，DM + SCIRI组的BMS和sub - BMS评分显著降低，NeuN表达减少，总移动距离缩短，运动减慢，proBDNF表达增加，且IL - 1β、IL - 6和TNF - α的mRNA水平升高（均P < 0.05或P < 0.01）。与DM + SCIRI + 溶媒组相比，DM + SCIRI + McAb - proB组的BMS和sub - BMS评分显著改善，且IL - 1β、IL - 6和TNF - α的mRNA表达降低（均P < 0.05或P < 0.01）。
高血糖通过上调proBDNF表达加重SCIRI中的神经损伤和炎症反应，延迟运动功能恢复。拮抗proBDNF表达可减轻糖尿病小鼠SCIRI后的神经损伤并促进功能恢复。
