Supplementary Material for: Cx40 Is Required for, and Cx37 Limits, Postischemic Hindlimb Perfusion, Survival and Recovery

Background/Aims: Ischemia induced by large-vessel obstruction or vascular injury induces a complex cascade of vasodilatory, remodeling and inflammatory pathways; coordination of these processes by vascular endothelium is likely to involve endothelial gap junctions. Vascular endothelium predominantly expresses two connexin (Cx) isoforms: Cx37 and Cx40. The relevance of these Cxs to postischemic limb recovery remains unclear. Methods: In this study, we use a well-established, severe femoral-saphenous artery-vein pair resection model of unilateral hindlimb ischemia to test the relevance of Cx37 and Cx40 to postischemic tissue survival and recovery of limb perfusion. Results: Cx40-deficient animals (Cx40–/–) experienced a severe reduction in limb perfusion relative to wild-type (WT) animals and exhibited profound and rapid failure of ischemic limb survival. By contrast, the deficit in limb perfusion was less severe in Cx37-ablated (Cx37–/–) animals compared to WT, corresponding with more rapid recovery of limb appearance and use. These results demonstrate that Cx40 is necessary for postischemic limb survival and reperfusion, whereas Cx37 deletion reduces the extent of ischemia in the same model. Conclusion: In summary, we present evidence demonstrating that Cx37 and Cx40 uniquely regulate postischemic limb perfusion, altering the severity of ischemic insult and consequent postischemic survival.

背景/目的：由大血管阻塞或血管损伤引起的缺血会导致一系列复杂的血管舒张、重塑和炎症途径的级联反应；血管内皮对这些过程的协调作用可能涉及内皮细胞间隙连接。血管内皮主要表达两种连蛋白（Cx）同型：Cx37和Cx40。这些Cx对缺血后肢体恢复的相关性尚不明确。方法：在本研究中，我们采用了一种成熟的、严重的单侧后肢缺血模型，即股-大隐静脉动脉-静脉对端吻合术模型，以测试Cx37和Cx40对缺血后组织存活和肢体灌注恢复的相关性。结果：Cx40缺乏型动物（Cx40–/–）与野生型（WT）动物相比，肢体灌注显著降低，并表现出缺血肢体生存的深刻且迅速的衰竭。相比之下，Cx37敲除型（Cx37–/–）动物的肢体灌注不足较野生型动物为轻，与肢体外观和功能的更快恢复相对应。这些结果表明，Cx40对于缺血后肢体的生存和再灌注是必要的，而Cx37的缺失在同一模型中降低了缺血的范围。结论：总之，我们提供了证据表明Cx37和Cx40独特地调节缺血后肢体灌注，改变了缺血损伤的严重程度及其导致的缺血后生存。