糖尿病创面中RAGE-巨噬细胞活化的效应关系对创面愈合进程的影响

Diabetic wound is characterized by an uncontrolled inflammation with impaired angiogenesis and disrupted reepithelialization. The modulation of macrophage activation phenotype plays a critical role in the progression from inflammation to repair process in wound healing. Our previous research showed the accumulation of advanced glycosylation end products (AGEs) in skin/wound tissue resulted from diabetic glycometabolic disorders induced oxidative stress through the receptor for AGEs (RAGE). It was related to the inflammatory reaction and tissue damage in diabetic wound. Macrophage is the target cell of ligand-RAGE. RAGE-positive inflammatory cells and altered macrophage activation phenotype were observed in our preliminary works. Thus, it was implicated that macrophage dysfunction mediated by RAGE may contribute to pathogenesis of the impaired transition from pro-inflammatory to pro-healing condition in diabetic cutaneous healing process. In this project the macrophage activation phenotype in diabetic wound healing and relationship between RAGE and macrophage activation will be further studied to establish the potential mechanism of impaired wound healing in diabetes. To investigate the impact of cutaneous glycosylated condition- - RAGE- - macrophage activation system on healing progression in diabetes may lead to a new potential target for therapeutic intervention to promote diabetic wound healing.

异常炎症反应伴修复迟滞是糖尿病难愈创面的重要病理特征，创面巨噬细胞是介导创面炎症向增殖期过渡的关键细胞，其不同活化状态可调控创面炎症转归和修复进程。前期工作示糖尿病糖代谢紊乱致糖基化终末产物蓄积于创面，经AGEs 受体（RAGE）介导的氧化应激效应与糖尿病创面呈现的异常炎症反应和组织受损现象相关；巨噬细胞是RAGE的重要靶细胞；糖尿病创面中炎性细胞高表达RAGE，且巨噬细胞活化表现异常，由此推测RAGE通过调控巨噬细胞活化状态介导创面炎症异常和修复阻滞。故本项目拟在阐明糖尿病创面愈合过程中巨噬细胞活化状态演变规律的基础上，研究RAGE与巨噬细胞异常活化之间的效应机制，探索RAGE激活-巨噬细胞活化-创面促炎/修复失衡的效应链，完善糖尿病创面异常炎症反应和修复进程阻滞的发生机制，明确糖尿病创面炎症转归的调控效应和作用环节，为终止糖尿病创面异常炎症反应、促使创面修复正常转归的临床干预提供靶点。

异常炎症反应伴修复迟滞是糖尿病难愈创面重要的病理特征。作为介导创面炎症向增殖期过渡的关键细胞-巨噬细胞，同时也是源于糖尿病代谢紊乱而蓄积于皮肤的糖基化终末产物（AGEs）与其受体RAGE 作用的重要靶细胞。通过观察糖尿病鼠全层皮肤缺损创面模型，结果显示，愈合过程中炎症细胞消退迟滞的糖尿病创面中，其巨噬细胞不仅呈现出“慢进慢出”的异常浸润特点，同时存在着不同极化表型间的过渡障碍。外源性局部应用RAGE抗体于糖尿病鼠难愈创面后，不仅改善了巨噬细胞的异常浸润与表型间的过渡障碍，同时也加速了创面中炎性细胞的清除，提示AGEs-RAGE-巨噬细胞介导创面中促炎/修复失衡及创面难愈。体外通过培养THP1细胞，进一步证实AGEs-RAGE 抑制了巨噬细胞吞噬能力，提高了M1促炎因子及M2生长因子的合成分泌能力，抑制了巨噬细胞向M2型极化。结合体内外研究结果，揭示了巨噬细胞通过吞噬和分泌功能在创面从炎症向增殖阶段过渡中起了关键作用，以不同的功能效应介导了创面的异常炎症转归而导致糖尿病创面难愈，证实了糖尿病创面环境中蓄积的AGEs——RAGE——巨噬细胞——糖尿病创面促炎/修复失衡的调控效应链，是导致糖尿病创面难愈的重要机制之一。另外，研究发现巨噬细胞表型标记物变化与其细胞功能改变并非完全一致，仅仅依靠表型标记物来界定巨噬细胞的极化状态可能会忽略其功能信息，且创面巨噬细胞极化功能状态受其所处环境影响，提示，改善创面愈合环境，早期炎症阶段调控巨噬细胞功能状态可能为一行之有效的促愈手段 ，为糖尿病难愈创面的临床干预治疗提供了新的思路.