He Yao, Chen Bai-li, Yang Rong-ping, Ren Ming, Zeng Zhi-rong
Department of Gastroenterology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2010 Feb;30(2):270-4.
To observe the occurrence and progression of liver fibrosis induced by pig serum exposure and bile duct ligation, and analyze the relationship between hepatic inflammation and liver fibrosis.
Chronically immune-mediated liver fibrosis was induced in rats by weekly injection of pig serum (IPS) into the peritoneal cavity at 3 ml/kg for 12 weeks. Cholestatic fibrosis was induced by common bile duct ligation (BDL). The Knodell score was used to evaluate the histological changes in the liver, and immunohistochemistry was performed using anti-SMA, anti-ED1, anti-CK7, and anti-CD45 antibodies. Quantitative real time PCR (qPCR) analysis was employed to quantify the mRNA expression of the genes related to inflammation, including interleukin-1beta (IL-1beta), IL-6, monocyte chemotactic protein-1, tumor necrosis factor-alpha, regulated upon activation normal T cell expressed and secreted (RANTES), transforming growth factor-beta, platelet-derived growth factor A, as well as the genes associated with fibrogenesis, namely collagen 1, alphaSMA, MMP-9 and TIMP-1.
Knodell scores for periportal necrosis, intralobular degeneration and focal necrosis, and portal inflammation were all significantly higher in the BDL group than in the IPS group (P<0.01), whereas the scores for fibrosis was higher in the IPS group (P<0.05). Immunohistochemistry showed obvious inflammation with numerous alphaSMA-positive cells in the liver of the rats in BDL group; the liver of the rats in IPS group showed numerous alphaSMA-positive myofibroblasts with limited inflammatory cell infiltration. qPCR demonstrated a significant up-regulation of the genes related to extracellular matrix remodeling such as collagen 1 (P<0.01), alphaSMA (P<0.01), MMP-9 (P<0.01) and TIMP-1 (P<0.01) in the rat liver in IPS group compared with those in the normal control group, and the mRNA expressions of the inflammation-related cytokines, except for RANTES, were comparable with those in the control. In contrast, the BDL group showed a significant up-regulation of all the pro-inflammatory genes examined with also increased expression of the fibrogenesis-related genes (P<0.05).
Liver fibrosis induced by IPS is characterized by active ECM remodeling in the absence of obvious inflammation, indicating that chronic development of liver fibrosis can be independent of active hepatic inflammation. BDL-induced liver fibrosis highlights obvious inflammation and fibrous proliferation in the liver.
观察猪血清暴露和胆管结扎诱导的肝纤维化的发生与进展，并分析肝脏炎症与肝纤维化之间的关系。
通过每周向大鼠腹腔内注射3 ml/kg猪血清（IPS），持续12周，诱导大鼠发生慢性免疫介导的肝纤维化。通过胆总管结扎（BDL）诱导胆汁淤积性纤维化。采用Knodell评分评估肝脏的组织学变化，并使用抗平滑肌肌动蛋白（anti-SMA）、抗ED1、抗细胞角蛋白7（anti-CK7）和抗CD45抗体进行免疫组织化学检测。采用定量实时聚合酶链反应（qPCR）分析来定量与炎症相关基因的mRNA表达，包括白细胞介素-1β（IL-1β）、IL-6、单核细胞趋化蛋白-1、肿瘤坏死因子-α、活化正常T细胞表达和分泌调节因子（RANTES）、转化生长因子-β、血小板衍生生长因子A，以及与纤维生成相关的基因，即胶原蛋白1、α平滑肌肌动蛋白（αSMA）、基质金属蛋白酶-9（MMP-9）和基质金属蛋白酶组织抑制因子-1（TIMP-1）。
BDL组门静脉周围坏死、小叶内变性和局灶性坏死以及门静脉炎症的Knodell评分均显著高于IPS组（P<0.01），而IPS组的纤维化评分更高（P<0.05）。免疫组织化学显示，BDL组大鼠肝脏有明显炎症，有大量αSMA阳性细胞；IPS组大鼠肝脏有大量αSMA阳性肌成纤维细胞，炎症细胞浸润有限。qPCR显示，与正常对照组相比，IPS组大鼠肝脏中与细胞外基质重塑相关的基因如胶原蛋白1（P<0.01）、αSMA（P<0.01）、MMP-9（P<0.01）和TIMP-1（P<0.01）显著上调，除RANTES外，炎症相关细胞因子的mRNA表达与对照组相当。相比之下，BDL组所有检测的促炎基因均显著上调，纤维生成相关基因的表达也增加（P<0.05）。
IPS诱导的肝纤维化的特征是在无明显炎症的情况下有活跃的细胞外基质重塑，表明肝纤维化的慢性发展可以独立于活跃的肝脏炎症。BDL诱导的肝纤维化突出了肝脏中明显的炎症和纤维增生。
