单核/巨噬细胞在腹膜纤维化中作用机制研究

Peritoneal fibrosis is the most important complication in maintenance of peritoneal dialysis(PD). Inflammation is a complex process and strongly associated with PD. Most studies were focused on the profibrotic cytokines released by inflammatroy cells. In addition to secreting the profibrotic cytokines,whether the inflammatroy cells themselves be directly associated with peritoneal fibrogenesis. In our previous study, we had demonstrated that co-culture of monocyte and HK-2 cell induced HK-2 cells transition. If there is a direct effect between peritoneal mesothelial cells(PMCs) and monocyte is still unknown. In this study we suppos that there is a cross-talk between monocyte/macrophage and PMCs，classically activated M1 macrophages and alternatively activated M2 macrophages may have different effect on PMCs, TLR4 played a key role in this process. We used monocyte/macrophage co-culture model and different rat mode to see whether monocyte/macrophgae had a direct effect on PMCs. Our results may provide a novel insight about the inflammation in preventing the progression of pertoneal fibrosis, and improve patient survival and provide a better quality of life.

腹膜纤维化是病人退出腹膜透析的主要原因。炎症反应是导致腹膜纤维化最常见的病因。既往关于腹膜纤维化的研究主要集中于炎症因子的作用。那么浸润的炎症细胞除了分泌炎症因子，是否还存在其他方式参与腹膜纤维化过程呢？我们前期的研究提示在体外单核/巨噬细胞与肾小管上皮细胞能通过直接接触发生相互作用。那么在腹膜透析过程中是否也存在单核/巨噬细胞与腹膜间皮细胞（PMCs）直接的相互作用？本实验假说：单核/巨噬细胞与腹膜间皮细胞两者互相激活；不同表型分化的巨噬细胞对PMCs具有不同的功能；TLR4介导单核/巨噬细胞与PMCs的相互作用。本实验利用不同表型分化的单核/巨噬细胞（M0，M1，M2）与PMCs共培养及不同的模式动物（腹膜纤维化大鼠、巨噬细胞敲除/回输大鼠及TLR4敲除小鼠）观察单核/巨噬细胞对PMCs表型、转分化指标及腹膜功能的影响，为临床治疗腹膜纤维化提供新的策略。

腹膜纤维化致超滤衰竭是持续性非卧床腹膜透析患者结束治疗的主要原因之一。因此，研究腹膜透析相关性腹膜纤维化的发生机制，对探索和防治腹膜纤维化、改善终末期肾病患者生存状态意义重大。本研究拟通过体外细胞共培养模拟单核/巨噬细胞与腹膜间皮细胞相互作用过程，观察不同表型分化巨噬细胞对腹膜间皮细胞形态及转分化的影响；通过高糖诱导建立腹膜纤维化小鼠模型及巨噬细胞敲除小鼠模型，在体内观察不同表型巨噬细胞对腹膜功能及纤维化的影响。结果发现：1.体外不同细胞因子可刺激M0细胞进行不同的表型分化，经典活化M1替代活化M2；2.M1型巨噬细胞通过直接接触方式诱导腹膜间皮细胞发生EMT；3.M1型巨噬细胞通过TLR4受体介导，MyD88非依赖信号通路介导腹膜间皮细胞EMT；4.巨噬细胞敲除能减轻小鼠腹膜纤维化的程度；5.M1型巨噬细胞回输导致腹膜纤维化加重，M2细胞回输导致腹膜纤维化程度减轻。此次研究结果表明不同表型巨噬细胞对腹膜功能及纤维化的影响，为我们今后临床抑制或阻断腹膜纤维化提供新的思路。