随意皮瓣远端缺血坏死中自噬的作用及其机制研究

The distal end of ultra-long random skin flap is prone to ischemia necrosis. However, its viable therapeutic drugs are quite scarce in clinic. The initiation of the endogenous protective mechanism in ischemic flap is the new direction for the promotion of random skin flap survival. Previously we demonstrated that the level of autophagy was up-regulated in the ischemic area of distal random skin flap in rats. What’s more, the treatment of calcitriol promotes random skin flap survival and stimulates autophagy as well (Sci Rep, 2016). But the effect of autophagy on distal random skin flap ischemia necrosis and its mechanism is unknown. On the basis of our previous research, firstly, we will evaluate the role of autophagy in distal random skin flap ischemia necrosis. Then we will regulate the level of autophagy to promote random skin flap survival. And the protective mechanism will be proved to increase angiogenesis and inhibit the leavel of apoptosis. After that, we will explore the relationship between AMPK-mTOR signaling pathway and autophagy induction in the ischemic area of random skin flap. Finally, we will demonstrate the protective mechanism of autophagy and the AMPK-mTOR signaling pathway for autophagy regulation in vitro. This study is to analyze the effect of autophagy on distal random skin flap ischemia necrosis and its mechanism, and to provide a theoretical basis of taking autophagy as a target for the treatment of random skin flap ischemia necrosis.

超长随意皮瓣远端容易发生缺血坏死，但临床上可行的治疗药物并不多。诱导缺血皮瓣启动内源性保护机制是促进随意皮瓣远端存活的研究新方向。本项目前期在大鼠超长随意皮瓣远端缺血区域发现自噬的激活；此外，骨化三醇促进随意皮瓣远端存活的同时，伴随缺血皮瓣自噬水平的提升（Sci Rep, 2016）。这提示自噬与随意皮瓣的存活有关联，但随意皮瓣远端缺血坏死中自噬的作用及其机制尚不清楚。本项目在前期研究基础上，首先探究自噬在随意皮瓣远端缺血坏死中的确切作用。然后，通过调控自噬促进随意皮瓣的存活，并验证其保护机制为促血管新生和抑制细胞凋亡。再者，研究缺血随意皮瓣中自噬的诱导与AMPK-mTOR信号通路的关联性。最后，在人体细胞模型中验证自噬的保护性机制及AMPK-mTOR信号通路对自噬的调控。本项目通过研究随意皮瓣远端缺血坏死中自噬的作用及其机制，可为以自噬为靶点促进随意皮瓣的存活提供理论依据。

超长随意皮瓣远端容易发生缺血坏死，但临床上可行的治疗药物并不多。诱导缺血皮瓣启动内源性保护机制细胞自噬是促进随意皮瓣远端存活的研究新方向。但随意皮瓣远端缺血坏死中自噬的作用及其机制尚不清楚。本研究首先探究自噬在随意皮瓣远端缺血坏死中的确切作用。然后，通过调控自噬促进随意皮瓣的存活，并验证其保护机制为促血管新生和抑制细胞凋亡。再者，研究缺血随意皮瓣中自噬的激活与AMPK-mTOR信号通路的关联性。最后，筛选激活自噬的活性药物，并研究其对随意皮瓣的存活、血管新生及细胞凋亡的影响。研究发现自噬的上调促进随意皮瓣远端缺血区域的存活。其次，细胞自噬通过促血管新生和抑制细胞凋亡，抑制随意皮瓣远端缺血坏死。此外，随意皮瓣远端缺血区域的自噬活性受到AMPK-mTOR-TFEB信号通路的调控。最后，研究发现多种激活自噬的药物对缺血皮瓣有显著促存活作用。具体如下，白藜芦醇，黄芪甲苷促进随意皮瓣远端区域的存活，并伴随组织内细胞自噬的激活；丹参酚酸B、桦木酸及骨化三醇分别通过激活细胞自噬，以促进超长随意皮瓣的存活；成纤维细胞生长因子21（FGF21）通过激活TFEB介导细胞自噬，以促进超长随意皮瓣的存活，且FGF21可能通过激活AMPK-mTOR及AMPK-SKP2-CARM1通路发挥作用。本项目首次成果阐释随意皮瓣远端缺血坏死中细胞自噬的作用及其调控机制。该成果对于将来随意皮瓣缺血坏死防治的临床转化及应用有着重要的意义。通过调控自噬诱导启动内源性保护机制，为随意皮瓣缺血远端的治疗提供一种新的思路。此外，开发或筛选激活细胞自噬的活性药物，以促进缺血随意皮瓣的活性，为该领域提供新的治疗策略。