游离组织瓣由于血管长时间缺氧损伤引起血管内皮细胞与平滑肌细胞功能紊乱，导致皮瓣危象，对患者的生活质量造成极大的影响。本课题组前期研究发现，低浓度的硝酸盐能够减少血管内皮细胞的缺氧损伤，提高细胞活性，促进增殖，抑制凋亡。本项目拟通过血管内皮细胞缺氧损伤模型，采用基因工程技术、分子生物学和细胞生物学相关技术研究硝酸盐在血管缺氧损伤中的作用及机制；提取硝酸盐干预缺氧损伤后血管内皮细胞的外泌体，分析外泌体中miRNAs的表达变化，将提取的外泌体与血管平滑肌细胞共培养，观察其对平滑肌细胞的影响；建立游离组织瓣缺氧损伤动物模型，分析并验证硝酸盐在组织瓣缺氧损伤中的保护机制。本项目有望揭示硝酸盐在缺氧损伤过程中对血管内皮细胞及平滑肌细胞的作用及机制，为临床采用硝酸盐疗法预防游离组织瓣缺氧损伤提供理论依据。

Crisis of free tissue flap can cause dysfunction of vascular endothelial cells and smooth muscle cells due to long-term hypoxia injury of blood vessels, which has a great impact on the life quality of patients. Our previous study found that low concentration of nitrate can reduce hypoxia injury of vascular endothelial cells, improve cell activity, promote proliferation and inhibit apoptosis.This project intends to study the role and mechanism of nitrate in hypoxia injury of vascular endothelial cells by gene engineering, molecular biology and cell biology technologies.The exosomes of vascular endothelial cells after intervention with nitrate after hypoxia injury were extracted to analyze the expression levels of miRNAs , and the extracted exosomes were co-cultured with vascular smooth muscle cells to observe the effects. Animal model of hypoxia injury of free tissue flap was established to analyze and verify the protective mechanism of nitrate in hypoxic injury of tissue flap.This project expected to reveal the effect and mechanism of nitrate on vascular endothelial cells and smooth muscle cells in the process of hypoxia injury, and provide a theoretical basis for the use of nitrate therapy to prevent hypoxia injury of free tissue flap in clinical.