The development of nanoparticles that can be used as stimuli-responsive drug carriers for the treatment of different diseases has been an emerging area of research. In this study, we designed a chitosan-bilirubin micelle (ChiBil) carrying losartan, which is responsive to intrinsic reactive oxygen species (ROS), for the treatment of hepatic fibrosis. Because bilirubin is hydrophobic in nature, its carboxyl group was conjugated to an amine group from chitosan using EDC-NHS chemistry to form an amphiphilic conjugate, ChiBil. Losartan is an angiotensin receptor blocker that reduces hepatic fibrosis, and it was used as the therapeutic payload in this study to form ChiBil-losartan micelles. The release characteristics of ChiBil-losartan were tested by ROS generation to confirm losartan release. Human hepatic stellate cell line LX2 was found to be the best in vitro model for the study. The reduction of hepatic stellate cell activation after treatment with ChiBil-losartan was analyzed based on the expression of alpha-smooth muscle actin (α-SMA) in both in vitro and in vivo studies. Advanced liver fibrosis was induced in C3H/HeN mice using a thioacetamide (TAA) via intraperitoneal injection and 10% ethanol (EtOH) in their drinking water. In addition, the hydroxyproline levels, histopathological evaluation, and mRNA quantification in the liver showed a decreased collagen content in the treated groups compared to that in the untreated control group. Macrophage infiltration studies and qPCR studies of inflammatory markers also proved the reduction of hepatic fibrosis in the treatment group. The intravenous administration of ChiBil-losartan resulted in decreased fibrosis in a TAA/EtOH-induced liver fibrosis mouse model. The in vitro and in vivo results suggest that the ROS stimuli-responsive ChiBil nanoparticles carrying losartan may be a potent therapeutic option for the treatment of hepatic fibrosis. The combined effect of losartan and bilirubin exhibited a decreased hepatic fibrosis both in vitro and in vivo.

可以用作刺激性药物载体以治疗不同疾病的纳米颗粒的开发已经成为新兴的研究领域。在这项研究中，我们设计了一种带有氯沙坦的壳聚糖-胆红素胶束（ChiBil），它对内在活性氧（ROS）有反应，用于治疗肝纤维化。由于胆红素本质上是疏水性的，因此使用EDC-NHS化学方法将其羧基与壳聚糖的胺基偶联，形成两亲性偶联物ChiBil。氯沙坦是一种可降低肝纤维化的血管紧张素受体阻滞剂，在本研究中被用作治疗有效载荷，以形成ChiBil-氯沙坦胶束。ChiBil-losartan的释放特性通过ROS生成进行了测试，以确认losartan的释放。发现人肝星状细胞系LX2是该研究的最佳体外模型。基于两种平滑肌肌动蛋白（α-SMA）的表达，分析了ChiBil-氯沙坦治疗后肝星状细胞激活的减少体外和体内研究。使用硫代乙酰胺（TAA）通过腹膜内注射和饮用水中的10％乙醇（EtOH）在C3H / HeN小鼠中诱导晚期肝纤维化。此外，与未治疗的对照组相比，治疗组的肝脏中羟脯氨酸水平，组织病理学评估和mRNA定量显示胶原蛋白含量降低。巨噬细胞浸润研究和炎性标志物的qPCR研究也证明了治疗组肝纤维化的减轻。在TAA / EtOH诱导的肝纤维化小鼠模型中，ChiBil-氯沙坦的静脉内给药导致纤维化减少。在体外和体内结果表明，携带氯沙坦的ROS刺激反应性ChiBil纳米颗粒可能是治疗肝纤维化的有效治疗选择。氯沙坦和胆红素显示出的联合作用均降低肝纤维化的体外和体内。