HPG肺移植保存液对移植肺的保护作用及其分子机制研究

Lung transplantation is the definitive treatment for almost all endstage lung diseases. The lung ,especially its tender alveolar is, more than other solid organs, susceptible for cold ischemia and reperfusion injury during preservation and orthotropic transplantation, thus more significant efforts have been made to optimize the methods for lung preservation in an attempt to minimize lung injury during the period of ischemia than other solid organs.We have previously shown that HPG,unlike HES, dextran and other linear polymers, is a compact biocompatible polymer, and has low intrinsic viscosity and could not only improve the ability of freezing resistance and membrane fluidity of cells,but also maintain a long-term effective colloid pressure at hypothermia. All of these properties suggest that HPG may be superior to dextran or HES for the cold storage of donor lungs in transplantation. This study is to investigate the possible protective effects and mechanisms of HPG based lung preservation solution on cold ischemia and reperfusion injury of donor lungs by canine lung transplantation model in vivo and isolated lung perfusion and hypoxia / reoxygenation injury model of human alveolar and pulmonary artery endothelial cells in vitro . The findings of this study might provide a new therapeutics strategy and a beneficial approach to optimize lung preservation solution in order to prolong lung preservative term and provide better protection and improve outcome after lung preservation and orthotropic transplantation.

肺移植是终末期肺部疾病的唯一有效治疗手段，但由于肺脏的特殊结构及肺泡上皮细胞的娇嫩性，移植肺保存难度要远远高于其他实质器官。申报者在前期研究工作中发现HPG具有提高细胞抗冷冻能力，保持低温下细胞膜的稳定性及维持长期有效胶体渗透压及无粘性和良好的组织相容性等不同于右旋糖酐和羟乙基淀粉的独特优点。本课题拟借助HPG这些独特的生物学特性,通过犬肺移植模型和离体肺缺血再灌注及肺泡上皮细胞和肺动脉内皮细胞缺氧复氧损伤细胞实验，探讨HPG肺移植保存液对移植肺的保护作用及其分子机制,以期为优化肺移植保存液，延长供肺安全保存时间，提高肺移植供肺保存效果提供一条新的策略和思路。

肺移植是终末期肺部疾病的唯一有效治疗手段，但由于肺脏的特殊结构及肺泡上皮细胞的娇嫩性，移植肺保存难度要远远高于其他实质器官。鉴于HPG具有提高细胞抗冷冻能力，保持低温下细胞膜的稳定性及维持长期有效胶体渗透压及无粘性和良好的组织相容性等独特优点，本课题通过建立肺移植动物模型及离体肺灌注和体外细胞实验，探讨了HPG肺保存液对移植肺的保护作用及其机制。本课题在成功建立大动物肺移植模型的基础上，创建了一种全新的肺移植支气管吻合方法，攻克了大动物肺移植模型的关键难点，操作方便快捷，值得推广。并通过细胞、器官和整体等不同水平研究，发现HPG肺保存液对移植肺有良好的保护作用，可使供肺安全保存时间延长至12h，并能显著改善移植后供肺通气换气功能，肺保护效果优于目前常用的LPD保存液。HPG肺保存液对移植肺的保护作用机制主要为：（1）HPG保存液提高冷保存及再灌注期间供肺超氧化物歧化酶（SOD）活性，降低丙二醛（MDA）含量，抑制供肺脂质过氧化反应。（2）HPG保存液可通过调节供肺Bax/Bcl-2比例和抑制caspase-3、caspase-9的表达减少线粒体途径诱导的肺细胞凋亡。（3）HPG保存液能有效抑制冷保存及再灌注期间供肺组织IL-1β等炎症细胞因子及细胞因子诱导的中性粒细胞趋化因子(CINC)表达，减少供肺免疫炎性反应。（4）HPG肺保存液可通过下调ET-1、VEGF、TNF-α等炎性细胞因子有效抑制氧化应激状态下肺动脉内皮和Ⅱ型肺泡上皮细胞的免疫炎性反应。本研究结果可望为优化肺移植保存液，提高肺移植供肺保存效果的研究提供一条新的思路和途径。