■高剂量照射是帮助控制肝肿瘤生长的重要工具,但它可以导致辐射诱发的肝脏疾病(RILD)。这种危及生命的并发症在放射治疗后数月表现出来,其特征是中心周围窦纤维化。在这项研究中,我们旨在建立RILD小鼠模型,以探讨放射性肝纤维化的潜在机制。
■使用小动物图像引导放射治疗平台,设计了一种将50Gy作为单剂量输送到小鼠肝脏焦点的照射方案。对组织进行了1天和6天的分析,照射后6周和20周。通过组织学评估辐照的肝脏,免疫组织化学,成像质量细胞计数和RNA测序。使用高分辨率呼吸测量法评估线粒体功能。
■在照射后6周和20周,在高度照射的区域可见中心周围纤维化,同时存在免疫细胞浸润和红细胞外渗。RNA测序分析显示与急性DNA损伤相关的基因特征,p53激活,衰老及其相关的分泌表型和纤维化。此外,检测到线粒体损伤的基因谱和线粒体DNA异质性的增加。体外肝细胞的呼吸测定证实了辐射诱导的线粒体功能障碍。最后,高度辐照的纤维化区域显示出活性氧的标志物,例如谷胱甘肽减少,脂质过氧化物增加和衰老样表型。
■基于我们的RILD小鼠模型,我们认为,辐射诱导的线粒体DNA不稳定性有助于纤维化的发展通过产生过量的活性氧,p53途径激活和衰老样表型。
■照射是一种有效的癌症疗法,然而,其对肝脏的适用性受到威胁生命的辐射诱导的肝纤维化的限制。我们开发了一种新的小鼠辐射诱导肝纤维化模型,概括了人类疾病。我们的模型强调了线粒体DNA不稳定性在辐射诱导的肝纤维化发展中的作用。这个新模型和随后的发现将有助于增加我们对肝脏对辐射的反应的理解,并找到保护肝脏的策略,使放射治疗的扩大使用,以治疗肝肿瘤。
UNASSIGNED: High-dose irradiation is an essential tool to help control the growth of hepatic tumors, but it can cause radiation-induced liver disease (RILD). This life-threatening complication manifests itself months following radiation therapy and is characterized by fibrosis of the pericentral sinusoids. In this study, we aimed to establish a mouse model of RILD to investigate the underlying mechanism of radiation-induced liver fibrosis.
UNASSIGNED: Using a small animal image-guided radiation therapy platform, an irradiation scheme delivering 50 Gy as a single dose to a focal point in mouse livers was designed. Tissues were analyzed 1 and 6 days, and 6 and 20 weeks post-irradiation. Irradiated livers were assessed by histology, immunohistochemistry, imaging mass cytometry and RNA sequencing. Mitochondrial function was assessed using high-resolution respirometry.
UNASSIGNED: At 6 and 20 weeks post-irradiation, pericentral fibrosis was visible in highly irradiated areas together with immune cell infiltration and extravasation of red blood cells. RNA sequencing analysis showed gene signatures associated with acute DNA damage, p53 activation, senescence and its associated secretory phenotype and fibrosis. Moreover, gene profiles of mitochondrial damage and an increase in mitochondrial DNA heteroplasmy were detected. Respirometry measurements of hepatocytes in vitro confirmed irradiation-induced mitochondrial dysfunction. Finally, the highly irradiated fibrotic areas showed markers of reactive oxygen species such as decreased glutathione and increased lipid peroxides and a senescence-like phenotype.
UNASSIGNED: Based on our mouse model of RILD, we propose that irradiation-induced mitochondrial DNA instability contributes to the development of fibrosis via the generation of excessive reactive oxygen species, p53 pathway activation and a senescence-like phenotype.
UNASSIGNED: Irradiation is an efficient cancer therapy, however, its applicability to the liver is limited by life-threatening radiation-induced hepatic fibrosis. We have developed a new mouse model of radiation-induced liver fibrosis, that recapitulates the human disease. Our model highlights the role of mitochondrial DNA instability in the development of irradiation-induced liver fibrosis. This new model and subsequent findings will help increase our understanding of the hepatic reaction to irradiation and to find strategies that protect the liver, enabling the expanded use of radiotherapy to treat hepatic tumors.