Salguero Palacios Rebeca, Roderfeld Martin, Hemmann Stefanie, Rath Timo, Atanasova Srebrena, Tschuschner Annette, Gressner Olav A, Weiskirchen Ralf, Graf Jürgen, Roeb Elke
Department of Medicine II, Gastroenterology, Justus-Liebig-University Giessen, University Hospital Giessen and Marburg, Giessen, Germany.
Lab Invest. 2008 Nov;88(11):1192-203. doi: 10.1038/labinvest.2008.91. Epub 2008 Sep 15.
The pathophysiological mechanisms of thioacetamide (TAA)-induced hepatic fibrogenesis are not yet fully understood. In particular, the role of hepatic stellate cells (HSCs) remains unclear. We therefore examined proliferation and transdifferentiation of HSC as well as the underlying molecular mechanisms in TAA-induced fibrosis. Hepatic fibrogenesis was induced in mice by addition of TAA to drinking water. Liver damage was determined by assessment of alanine aminotransferase and aspartate aminotransferase levels, and measurement of collagen deposition. Additionally, expression patterns of alpha-smooth muscle actin, glial fibrillary acidic protein (GFAP, specific hepatic biomarker for HSC), cysteine- and glycine-rich protein 2 (CRP2, specific marker of HSC transdifferentiation), tissue inhibitor of metalloproteinases-1, matrix metalloproteinase-9 (MMP-9), interleukins (IL-1beta, IL-6), platelet-derived growth factors (PDGF-B, PDGF-D) , tumor necrosis factor (TNF)-alpha, and (transforming growth factor (TGF)-beta1 were assessed by real-time PCR. Transcription of GFAP and CRP2 were transiently upregulated during TAA-induced fibrogenesis (punctum maxima (p.m.) week 10 for GFAP and week 14 for CRP2). Similar transient expression patterns were demonstrated for IL-1beta, IL-6, TGF-beta1, and PDGF-B (p.m. week 12) whereas TNF-alpha and PDGF-D continuously increased with ongoing liver injury. In particular, not only neutrophil granulocytes, but also macrophages and leukocytes served as a major source for MMP-9 expression. GFAP and CRP2 expression patterns demonstrated transiently increased HSC-activation during TAA-induced hepatic fibrogenesis. The rate of increase of transcription of GFAP correlated best with PDGF-B, whereas CRP2 levels correlated with PDGF-B, PDGF-D, and IL-1beta expression. This study demonstrates for the first time that transiently increased activation patterns of HSC are observed in toxically induced hepatic fibrosis. Thus, TAA in drinking water is an effective and elegant model to induce reproducible states of liver fibrosis without parenchymal damage in mice.
硫代乙酰胺（TAA）诱导肝纤维化的病理生理机制尚未完全明确。尤其是肝星状细胞（HSC）的作用仍不清楚。因此，我们研究了TAA诱导纤维化过程中HSC的增殖和转分化以及潜在的分子机制。通过在小鼠饮用水中添加TAA诱导肝纤维化。通过评估丙氨酸氨基转移酶和天冬氨酸氨基转移酶水平以及测量胶原沉积来确定肝损伤。此外，通过实时PCR评估α-平滑肌肌动蛋白、胶质纤维酸性蛋白（GFAP，HSC的特异性肝脏生物标志物）、富含半胱氨酸和甘氨酸的蛋白2（CRP2，HSC转分化的特异性标志物）、金属蛋白酶组织抑制剂-1、基质金属蛋白酶-9（MMP-9）、白细胞介素（IL-1β、IL-6）、血小板衍生生长因子（PDGF-B、PDGF-D）、肿瘤坏死因子（TNF）-α和转化生长因子（TGF）-β1的表达模式。在TAA诱导的纤维化过程中，GFAP和CRP2的转录瞬时上调（GFAP在第10周达到峰值，CRP2在第14周达到峰值）。IL-1β、IL-6、TGF-β1和PDGF-B表现出类似的瞬时表达模式（在第12周达到峰值），而TNF-α和PDGF-D随着肝损伤的持续而持续增加。特别是，不仅中性粒细胞，而且巨噬细胞和白细胞都是MMP-9表达的主要来源。GFAP和CRP2的表达模式表明，在TAA诱导的肝纤维化过程中HSC激活瞬时增加。GFAP转录的增加速率与PDGF-B相关性最好，而CRP2水平与PDGF-B、PDGF-D和IL-1β表达相关。本研究首次证明，在毒性诱导的肝纤维化中观察到HSC激活模式瞬时增加。因此，饮用水中的TAA是一种有效且简便的模型，可在小鼠中诱导可重复的肝纤维化状态而无实质损伤。
