KLF2介导外泌体递送miR-23b在低温机械灌注中改善DCD供肝质量的作用及机制研究

肝移植是终末期肝病最有效的治疗手段，如何有效地修复心脏死亡供体（DCD）供肝损伤、改善供肝质量，减少丢弃率是亟待解决的核心问题。本课题前期研究发现，低温机械灌注（HMP）能有效地保护DCD供肝的功能,但其机制尚不清楚。HMP可明显改善供肝的功能及炎症反应，大鼠肝脏经热缺血损伤后Kruppel样因子2（KLF2）表达明显下降，内皮细胞在层流刺激下可显著增强KLF2的表达抑制炎症反应。由此推测：HMP通过层流刺激使血管内皮细胞中的KLF2表达上调，KLF2从胞浆迁移到细胞核内使miR-23b表达上调，miR-23b通过外泌体的形式调节内皮细胞与炎症细胞的相互作用，抑制炎症反应，从而改善DCD供肝质量。本项目拟采用大鼠DCD供肝和大鼠肝窦内皮细胞及巨噬细胞建立HMP模型，观察HMP对DCD供肝的保护作用，阐明其保护作用的机制，为HMP的临床应用提供理论支持。

Liver transplantation is the most effective treatment for end-stage liver diseases.Thus, how to effectively repair the DCD donor liver injury, improve the quality of donor liver and reduce the liver discarding rate remain the key problem to be solved.Our previous study proved that hypothermic machine perfusion (HMP) can effectively protect the function of DCD donor liver, but its the underlying mechanisms  are not clear. The function and inflammatory situation of the donor liver can be significantly improved by HMP. The expression of Kruppel like factor2 (KLF2) significantly decreased after warm ischemia injury. And laminar flow stimulus significantly enhanced KLF2 expression and inhibited inflammatory response in endothelial cells.Therefore, it is speculated that HMP might enhance KLF2 expression in vascular endothelial cells through laminar flow stimulus, then KLF2 migrates from cytoplasm to nucleus and up-regulates miR-23b level, which regulates the interaction between endothelial cells and inflammatory cells by exosomes and further inhibits inflammation and improves the quality of DCD donor liver. The present study aims to establish a HMP model using rat DCD donor liver, rat sinusoidal endothelial cells and macrophages, observe the protective effect of HMP on DCD donor liver and elucidate the protective mechanisms through molecular biology techniques, in order to provide theoretical support for the application of HMP in liver transplantation.