靶向下调胸节脊髓lncRNA表达：保护CPB心肌缺血再灌注损伤的新策略

Myocardial ischemia-reperfusion injury with cardiopulmonary bypass (CPB-MI/RI) is an important risk factor for cardiac surgery, which may lead to severe circulatory sequela, and even cause direct mortality of patients. However, until now there is no effective way to prevent or treat CPB-MI/RI. It has been reported that chronic spinal cord stimulation modifies intrinsic myocardial synaptic efficacy and cardiac autonomic nervous system activity changes. Our previous researchers have found that the expression of thoracic spinal lncRNA was increased after CPB-MI/RI, which was involved in the reperfusion injury-related inflammatory response. Therefore, this project raises a presumption: abnormal expression of specific lncRNA in spinal cord may play a key role in the control of CPB-MI/RI. In the present study, by establishing a rat model of myocardial ischemia-reperfusion injury with CPB, we observe XR_345533.2 expression in the spinal cord and its associated injuries. We then inhibit spinal XR_345533.2 expression by using XR_345533.2-siRNA to investigate potential protective effects on the myocardial cells and related signaling pathways. Furthermore, we try to understand the metabolic mechanisms of spinal LncRNAs participating in the myocardial ischemia-reperfusion injury with CPB by 1HNMR metabolomics. Studying the pathogenic mechanism and molecule-targeted intervention of CPB-MI/RI, may provide new strategies for a safe and effective therapeutic precept of CPB-MI/RI in cardiac surgery.

体外循环(CPB)心肌缺血再灌注损伤是影响心脏手术病人康复的重要危险因素，可引起循环系统严重后遗症，甚至直接威胁病人生命。然而，这种损伤目前尚无有效的防治手段。已有报道脊髓电刺激可以调控心肌突触效能和心脏自主神经节活性变化。申请者前期研究发现CPB心肌缺血再灌注损伤，通过支配心脏的神经引起上胸节脊髓lncRNAs的表达变化，其中XR_345533.2表达增加并参与心肌缺血再灌注损伤相关的炎性反应。因此提出假设：脊髓特异性lncRNAs表达异常在CPB心肌缺血再灌注损伤的调控中起重要作用。本项目拟建立大鼠体外循环(CPB)模型，给予XR_345533.2-siRNA局部沉默脊髓lncRNA，观察下调脊髓XR_345533.2对CPB心肌损伤的保护作用及机制，并运用1HNMR代谢组学阐明脊髓lncRNAs参与CPB心肌缺血再灌注损伤中的代谢机制，为CPB心脏手术的心肌保护机制提供一种新策略。

体外循环(CPB)心肌缺血再灌注损伤是影响心脏手术病人康复的重要危险因素，可引起循环系统严重后遗症，甚至直接威胁病人生命。然而，这种损伤目前尚无有效的防治手段。本项目是研究脊髓特异性lncRNAs表达异常在CPB心肌缺血再灌注损伤的调控中起重要作用。将SD大鼠分为对照组、心肌缺血再灌注损伤（IR）组、CPB组、CPB-XR_345533.2-siRNA组。运用转录组学、蛋白质组学和代谢组学去观察下调脊髓XR_345533.2对CPB心肌损伤的保护作用及机制。与对照组相比，IR组和CPB组血清肌钙蛋白水平明显升高，且心肌TTC染色发现梗死心肌组织，HE染色显示IR组和CPB组心肌细胞排列紊乱，可见炎症细胞浸润，而siRNA组上述指标则明显好于IR组和CPB组。NMR代谢组学分析发现与相比，IR组大鼠上胸段（T1-6）脊髓牛磺酸含量高于对照组(2.84±0.16 vs. 3.53±0.16 μmol/g, p=0.011),而且上胸段脊髓谷氨酸/牛磺酸的比值(1.17±0.04 vs. 1.37±0.08, p=0.043)、谷氨酸/(γ-氨基丁酸+牛磺酸)的比值(0.71±0.01 vs. 0.78±0.03, p=0.048)低于Control组。牛磺酸、甘氨酸和谷氨酸可能参与脊髓lncRNAs对心肌缺血再灌注损伤的调控；脊髓谷氨酸/牛磺酸、谷氨酸/(γ-氨基丁酸+牛磺酸)的比值可能作为心肌缺血再灌注损伤的潜在标志物。研究CPB-IR的致病机制和分子靶向干预，可能为心脏手术中IR的治疗方案提供新的策略。