白头翁汤调控Rho/ROCK信号通路治疗放射性肠炎的机制研究

Radiation enteritis is an inrestinal complication after radiotherapy beacause of abdominal, pelvic retroperitoneal malignant tumor. There are fibrosis, luminal stenosis or perforation, abscess, fistula and intra-abdominal intestinal adhesion formation in the advanced stages of the disease, severely affect the quality of life of patients. Radiation in Chinese medicine is a " heat toxin ", it's pathogenesis is ray of toxin invasion, toxic heat flourishing.Pulsatilla decoction from " treatise on Febrile Diseases ",with heat-clearing and detoxicating, cooling blood to stop diarrhea treatment, a large number of clinical experiments have proved that the treatment of this disease is exact, but the mechanism of its anti fibrosis are not reported. This project aims to construct radioactivity enteritis fibrosis model rats, selected in the model induced fibrosis related factor; in the mechanism of action in vivo and in vitro study of Pulsatilla decoction, specific occurred in the development of fibrosis in different periods; and further to explore whether Pulsatilla Decoction on Rho/ ROCK pathway play a role. In order to study the potential protective effects of pelvic tumor after radiotherapy in patients with rectal fibrosis, for its application to provide a theoretical basis for radiation protection.

放射性肠炎(RE)是盆腔、腹腔、腹膜后恶性肿瘤经放射治疗引起的肠道并发症。晚期肠壁引起纤维化，肠腔狭窄或穿孔，腹腔内形成脓肿、瘘道和肠粘连等严重影响患者的生存质量。放射线在中医属"火热毒邪"，RE病机为射线之邪毒侵袭，热毒炽盛，灼伤经络，热毒深陷血分，下迫大肠。而出自《伤寒论》的经典名方白头翁汤,以清热解毒，凉血止痢为治则，大量临床实验已证明其治疗本病疗效确切，但对其抗纤维化的机制尚未见研究报道。本课题拟构建大鼠放射性肠炎纤维化模型，筛选出该模型中的致纤维化相关因子，于在体和离体具体研究白头翁汤在RE纤维化发生、发展不同时期的作用机制，并进一步探讨白头翁汤是否对Rho/ROCK 通路发挥作用，从而研究白头翁汤对肿瘤患者盆腔放疗后直肠纤维化的潜在保护作用，为其应用于放射防护提供理论基础。

放射性肠炎是盆腔、腹腔、腹膜后恶性肿瘤经放射治疗引起的肠道并发症。晚期肠壁引起纤维化，肠腔狭窄或穿孔，腹腔内形成脓肿、瘘道和肠粘连等严重影响患者的生存质量。建立大鼠放射性直肠纤维化模型，通过在体和离体实验，研究相关纤维化因子及蛋白表达来探索Rho/ROCK信号通路在其中发挥的作用。通过观察纤维化相关细胞的增殖、迁移、表型转变和直肠胶原代谢的相关因子的表达，来探讨白头翁汤对放射性直肠纤维化发生、发展的影响。在体内实验中，白头翁汤能改善大鼠肠粘膜的炎症、水肿、充血；减少胶原纤维增生；减少肥大细胞增生，可能机制是它下调了纤维化相关因子CollagenI、TGF-β1、Smad3的表达的同时也下调了Rho/ROCK信号通路RhoA、ROCK1和ROCK2的表达，Smad3可能是Rho/ROCK通路的下游靶分子。在体外实验中，白头翁汤改善纤维化可能是其降低了细胞的增殖及迁移；下调了α-SMA、RhoA、ROCK1、ROCK2、CollagenI的表达。对于ROCK不同亚型的干扰，除了在成纤维细胞中ROCK1-siRNA干扰未见明显作用，其余两类细胞的ROCK1-siRNA干扰及三类细胞的ROCK2-siRNA干扰均抑制了细胞的增殖。综合体内及体外实验，说明白头翁汤能通过抑制Rho/ROCK信号通路抑制 RhoA的表达，而使下游ROCK1和ROCK2的表达不同下调，减少纤维化相关因子的表达，并使细胞增殖及迁移能力下调，TGF-β可通过Rho/ROCK通路介导肌成纤维细胞表型转变使成纤维细胞表型转变减少，达到减少细胞外基质的生成，改善肠粘膜炎症水肿，减少胶原纤维，最终达到改善肠道纤维化的作用。在此我们阐述了白头翁汤治疗放射性肠炎的作用机制，为以后的进一步研究提供了可靠的依据。