Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass.
Department of Cardiac Surgery, Boston Children's Hospital, Boston, Mass; Harvard Medical School, Boston, Mass.
J Vasc Surg. 2020 Mar;71(3):1014-1026. doi: 10.1016/j.jvs.2019.03.079. Epub 2019 Jul 26.
Acute limb ischemia (ALI), the most challenging form of ischemia-reperfusion injury (IRI) in skeletal muscle tissue, leads to decreased skeletal muscle viability and limb function. Mitochondrial injury has been shown to play a key role in skeletal muscle IRI. In previous studies, we have demonstrated that mitochondrial transplantation (MT) is an efficacious therapeutic strategy to replace or to augment mitochondria damaged by IRI, allowing enhanced muscle viability and function in cardiac tissue. In this study, we investigated the efficacy of MT in a murine ALI model.
C57BL/6J mice (male, 10-12 weeks) were used in a model of ALI. Ischemia was induced by applying a tourniquet on the left hindlimb. After 2 hours of ischemia, the tourniquet was released, and reperfusion of the hindlimb was re-established; either vehicle alone (n = 15) or vehicle containing mitochondria (n = 33) was injected directly into all the muscles of the hindlimb. Mitochondria were delivered at concentrations of 1 × 10 to 1 × 10 per gram wet weight to each muscle, and the animals were allowed to recover. Sham mice received no ischemia or injections but were anesthetized for 2 hours and allowed to recover. After 24 hours of recovery, limb function was assessed by DigiGait (Mouse Specifics Inc, Boston, Mass), and animals were euthanized; the gastrocnemius, soleus, and vastus medialis muscles were collected for analysis.
After 24 hours of hindlimb reperfusion, infarct size (percentage of total mass) and apoptosis were significantly decreased (P < .001, each) in the gastrocnemius, soleus, and vastus medialis muscles in MT mice compared with vehicle mice for all mitochondrial concentrations (1 × 10 to 1 × 10 per gram wet weight). DigiGait analysis at 24 hours of reperfusion showed that percentage shared stance time was significantly increased (P < .001) and stance factor was significantly decreased (P = .001) in vehicle compared with MT and sham mice. No significant differences in percentage shared stance time (P = .160) or stance factor (P = .545) were observed between MT and sham mice.
MT ameliorates skeletal muscle injury and enhances hindlimb function in the murine model of ALI.
急性肢体缺血（ALI）是骨骼肌组织中最具挑战性的缺血再灌注损伤（IRI）形式，导致骨骼肌活力和肢体功能下降。线粒体损伤已被证明在骨骼肌 IRI 中起关键作用。在之前的研究中，我们已经证明线粒体移植（MT）是一种有效的治疗策略，可以替代或增强因 IRI 而受损的线粒体，从而提高心肌组织的肌肉活力和功能。在这项研究中，我们研究了 MT 在鼠类 ALI 模型中的疗效。
使用 C57BL/6J 小鼠（雄性，10-12 周）建立 ALI 模型。通过在左后肢上应用止血带诱导缺血。缺血 2 小时后，松开止血带，重新建立后肢再灌注；单独给予载体（n=15）或含有线粒体的载体（n=33）直接注入后肢所有肌肉。线粒体以每克湿重 1×10 到 1×10 的浓度递送至每个肌肉，并允许动物恢复。假手术小鼠不接受缺血或注射，但接受 2 小时麻醉并允许恢复。恢复 24 小时后，通过 DigiGait（Mouse Specifics Inc，马萨诸塞州波士顿）评估肢体功能，然后处死动物；收集比目鱼肌、跖肌和股四头肌进行分析。
后肢再灌注 24 小时后，与载体小鼠相比，所有线粒体浓度（1×10 至 1×10 每克湿重）下，MT 小鼠的比目鱼肌、跖肌和股四头肌的梗死面积（占总质量的百分比）和细胞凋亡明显减少（P<0.001，各）。再灌注 24 小时的 DigiGait 分析显示，与 MT 和假手术小鼠相比，载体小鼠的共享支撑时间百分比明显增加（P<0.001），支撑因子明显降低（P=0.001）。MT 和假手术小鼠之间的共享支撑时间百分比（P=0.160）或支撑因子（P=0.545）无显著差异。
MT 可改善骨骼肌损伤并增强鼠类 ALI 模型的后肢功能。
