Toll样受体4对腹膜间皮细胞纤维化的影响机制

Peritoneal fibrosis (PF) is a major complication of the peritoneal dialysis(PD), causes the ultrafiltration failure, eventually leading to exit the peritoneal dialysis. peritoneal mesothelial cells(PMCs) damage such as cell detachment, epithelial to mesenchymal transition is a leading cause of PF. So elucidation the high glucose effect in PMCs is a major step in the pathogenesis of PF. Recent study reported that Inflammatory cytokines and inflammatory reaction had become a new viewpoint in PD related peritonitis, but the molecular mechanism of inflammation mediatd PMCs injury and PF is not cleare yet. In this study, we based on TLR4 silencing PMCs and TLR4 knockout animals，to observe TLR4 expression, inflammatory mediator secretion, extracellular matrix synthesis and degradation, PMCs apoptosis, ROS related gene expression, TLR4 down-stream gene expression in PMCs under high glucose condition. Sequentially to define the function system of TLR4 on PMCs damage and extracellular matrix accumulation, and farther confirm this results through clinical research. It not only help to elucidate the pathogenesis of PD related peritonitis, but also offers a new way for prognosis and gene therapy in PD related peritonitis.

腹膜纤维化（PF）是腹膜透析(PD)的主要并发症，导致超滤失败，最终导致患者退出腹膜透析，而腹膜间皮细胞损伤（PMCs）如脱落、转分化等原因是导致PF的主要原因。因此进行高糖对PMCs作用的分子机制研究是预防及延缓PF的关键环节之一。近年来炎症因子及炎症反应成为腹膜透析相关性腹膜炎的新视点，但炎症反应介导PMCs损伤、纤维化的确切的分子生物学机制尚不明确。本文利用RNA干扰抑制TLR4基因表达的PMCs及TLR4基因敲除动物模型为模板，观察高糖条件下PMCs中TLR4基因的变化，观察PMCs炎症介质分泌、细胞外基质合成及降解、PMCs凋亡、ROS相关基因及TLR4下游基因的表达变化，明确TLR4对PMCs损伤及细胞外基质积聚的作用，并通过临床实验进一步验证。这将为进一步阐明腹膜透析相关性腹膜炎的发病机制以及预后判定、基因治疗提供一种新途径。

腹膜透析基础是腹膜结构与功能的稳定，而长期腹膜透析往往导致腹膜纤维化从而限制其在临床上的应用。如何维持腹膜的功能，延长腹膜透析时间成为我们面临的主要问题。近年来发现长腹膜间皮细胞无菌性炎症反应是腹膜纤维化的主要原因。Toll样受体通过识别损伤相关分子模式分子（DAMPs）介导无菌性炎症反应。本研究发现，高糖刺激下腹膜间皮细胞中TLR4蛋白表达增多，而抑制TLR4蛋白的表达，可改善高糖刺激所致的FN等细胞外基质的表达，从而明确了TLR4与高糖所致的腹膜间皮细胞纤维化密切相关。实验组进一步发现抑制TLR4的表达可抑制ERK、JNK及P38、IκB磷酸化，还可减少腹膜间皮细胞的凋亡。因此，TLR4对腹膜间皮细胞纤维化的影响研究，将有助于进一步了解腹膜透析相关腹膜纤维化的分子生物学机制，这为腹膜透析相关性腹膜纤维化的诊断及治疗开辟了崭新的前景。