微小核醣核酸在缺血缺氧皮瓣之角色探討與機轉研究

Study on the role and mechanism of microRNAs in the ischemic and hypoxic regional flap

張智豪(Chih-Hau Chang)

指導教授 ： 許雅玲

高雄醫學大學/醫學院/醫學研究所博士班/博士(2020年)

摘要

重建軟組織缺損至傷口癒合為整形外科常見且充滿挑戰的領域，常因外傷，糖尿病足，移植及癌症所造成傷口癒合困難進而演變為未癒合困難傷口。
目前於臨床上主要解決困難傷口的方法為自由皮瓣手術，使用自體軟組織重建至受傷缺損部位，避免神經、骨頭和肌腱等重要組織暴露及感染亦或填補癌症切除大範圍傷口並修復功能，而手術成功與否，取決於如何降低所取組織的缺血再灌流損傷及避免組織末端缺血缺氧以降低血管內皮細胞損傷進而減少血栓形成，並使皮瓣手術後的纖維母細胞增生促進傷口癒合。而目前臨床手術仍無法完全避免這些影響傷口癒合的因子。故此研究聚焦於缺血再灌注損傷，及皮瓣組織末端邊緣因血液循環不足缺血所造成壞死，利用基礎研究探討微小核醣核酸(microRNAs)如何促進缺血皮瓣的血管新生亦或促進纖維母細胞的增生的分子生物學路徑，其結果將可應用於降低手術後皮瓣邊緣壞死之術前預防及術後補救方法，或可能應用於慢性停滯性傷口的組織再生癒合。
本研究基於缺氧缺血再灌流之大鼠腹部皮瓣模型，分析血液循環良好的皮瓣組織，經由缺氧缺血再灌注損傷後的組織，發現有四個microRNAs表現量呈現有意義的升高，並進一步發現在72小時後兩條miRNA包含miR-21-5p，miR-210-3p表現隨時間及組織缺氧缺血程度呈正相關且扮演顯著向上調控，故推論這兩種microRNAs於缺氧損傷後的組織間必定扮演重要之角色
本研究顯示，在缺氧缺血組織中微小核醣核酸miR-21和miR-210的表達是組織癒合之關鍵，不論經由SMAD7調控血管新生作用或調控FOBX31影響纖維母細胞再生作用，於此實驗中皆證實其扮演之角色，於未來之臨床運用為缺血在灌注損傷,缺氧及傷口癒合困難之生物標記運用為潛力目標。

關鍵字

微小核醣核酸 ； 缺血再灌注損傷 ； 缺氧 ； 困難傷口 ； 血管新生 ； 纖維母細胞 ； 傷口癒合

並列摘要

The large tissue defects are the most challenging field of the reconstruction, including the trauma, diabetic foot, transplantation, and cancer reconstruction. At present, the main clinical solution to difficult wounds is free flap surgery, the use of autologous soft tissue to reconstruct the injured defect, to avoid the nerves, bones, and tendons, and other important tissue free from exposure and infection as well as cancer reconstruction. The issue of the surgical failure is ischemia-reperfusion injury (IRI) by ischemia time, the flap distal margin necrosis by prolonging ischemia, and thrombosis due to apoptosis of vascular endothelial cells. These unpreventable factors caused an unhealed wound by reducing angiogenesis and dumping fibroblast proliferation until now. Therefore, we focus on ischemia-reperfusion injury of the ischemic flap since insufficient blood circulation. To investigate the insight mechanism of the microRNAs could salvage ischemic flap by increasing angiogenesis or fibroblasts proliferation; unlock these molecular pathways will benefit preoperative prevention and reduce postoperative flap edge necrosis in tissue engineering to heal the difficult wounds. In this study, we found four overexpressed microRNAs in ischemia rat flap after IRI. MiR-21-5p and miR-210-3p will be upregulated after 72 hours dependent on the severity of ischemic level. The pivot data revealed that miR-21-5p directly moderate the SMAD7 to increase the angiogenesis of hypoxic human umbilical vein endothelial cells (HUVEC) and miR-210-3p increased fibroblast proliferation via blocking FOBXO31, thus we conclude these two microRNAs will be potential therapeutic biomarkers applied in IRI, tissue ischemia and unhealed difficult wound.

並列關鍵字

microRNAs ； hypoxia ； ischemia/Reperfusion injury ； difficult wound ； angiogenesis ； fibroblast ； wound healing

參考文獻

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