氧应激诱导胰腺星状细胞活化及胰腺纤维化的机制研究

The knowledge on pathogenesis of chronic pancreatitis (CP) has been advanced in recent years mainly due to the identification of pancreatic stellate cells (PSCs) and their pivotal role in the fibrotic process of CP. Accumulated evidence suggests that oxidative stress is critically involved in the activation of PSCs and therapeutic approaches based on targeting oxidative stress pathways have been developed in the clinical setting of CP. However, the efficacy of anti-oxidant therapy is limited perhaps due to the fact of the poor identification of precise targets for treatment..Our current study planed to create a rat model of chronic pancreatic oxide injury induced by a chronic HFD. The sequential histopathologic changes and pancreatic fibrosis will be observed. Pancreatic stellate cells (PSCs) will be identified and the activation of PSCs will be studied. The levels of pancreatic lipid peroxidation F2-isoprostanes will be measured. The effects of the F2-isoprostanes on PSCs activation will be studied both in vivo and in vitro. The expression of Thromboxane A2 (TxA2r) in activated PSCs in vivo and in vitro will be measured. The mechanistic studies will be performed to prove if F2-isoprostanes could possess TxA2 receptor to induce specific intracellular signal transduction pathways responsible for inflammatory cellular alternations . Further efforts should be made to investigate the underlying precise mechanisms involved in the PSCs activation and pancreatic fibrosis induced by the lipid peroxidation. .The aims of our current study were designed to (1) to provide more evidences of oxidative stress and lipid peroxidation in the pathogenesis of CP, and (2) to investigate more critical molecules as potential targets for more effective anti-oxidant therapy.

胰腺星状细胞在胰腺纤维化中发挥关键作用，目前倡导将慢性胰腺炎治疗模式转化为针对胰腺星状细胞的靶向治疗。研究表明氧应激是诱导胰腺星状细胞活化的重要因素，抗氧化治疗已初步应用临床，但治疗靶点不明确。①本研究建立长期高脂饮食诱导的慢性胰腺氧化损伤动物模型，连续动态观察胰腺细胞损伤、星状细胞活化及纤维化过程；②测定脂质过氧化产物F2-异前列腺素水平，检测模型氧应激状态，并与胰腺组织中胶原表达行相关性分析；③通过胰腺星状细胞体外研究，观察F2-异前列腺素对细胞生物学功能的影响；④测定胰腺星状细胞中F2-异前列腺素相关受体（血栓素A2受体）的表达，并探讨F2-异前列腺素是否通过血栓素A2受体诱导胰腺星状细胞活化及其可能参与的信号通路，为临床抗氧化治疗慢性胰腺炎提供治疗"靶点"和理论依据。本课题将在体与离体研究相结合，弥补离体研究不能反映细胞真实生存环境的不足。

胰腺星状细胞在胰腺纤维化中发挥关键作用，目前倡导将慢性胰腺炎治疗模式转化为针对胰腺星状细胞的靶向治疗。研究表明氧应激是诱导胰腺星状细胞活化的重要因素，抗氧化治疗已初步应用临床，但治疗靶点不明确。本研究建立长期高脂饮食诱导的慢性胰腺氧化损伤大鼠动物模型，形态学观察发现大鼠胰腺发生纤维化损伤，胰腺组织中胰腺星状细胞显著活化，数量增多，并且发现胰腺纤维化区域脂质过氧化产物4-HNE的含量显著增加，提示氧应激（脂质过氧化反应）在诱导胰腺星状细胞活化及胰腺纤维化过程中发挥重要作用。同时研究还发现活化的胰腺星状细胞中TXA2受体的表达增加。实验又进一步进行胰腺星状细胞的体外分离培养，通过细胞免疫组化染色发现胰腺星状细胞表面存在TXA2受体的表达。通过在培养的胰腺星状细胞中施加脂质过氧化产物F2-异前列腺素发现，胰腺星状细胞增殖活化明显增加；如果在培养的胰腺星状细胞中施加TXA2受体的特异性抑制剂SQ29548，RT-PCR研究发现胰腺星状细胞中α-SMA的表达下降，Ⅰ型和Ⅲ胶原蛋白含量下降；这些研究结果提示TXA2受体在胰腺星状细胞活化过程中发挥重要作用，探明其信号通路非常重要。故进一步通过MAPS方法筛查在以上实验过程中发生变化的基因，并探讨其可能的信号通路，为进一步针对胰腺星状细胞的靶向治疗提供靶点。