Bruck Rafael, Schey Ron, Aeed Hussein, Hochman Ayala, Genina Olga, Pines Mark
Department of Gastroenterology, The E. Wolfson Medical Center, Holon, Israel.
Liver Int. 2004 Apr;24(2):169-76. doi: 10.1111/j.1478-3231.2004.00900.x.
Nuclear factor kappa B (NF-kappaB) activation, proinflammatory cytokines, and reactive oxygen species have been implicated as mediators of liver injury and fibrogenesis. We have shown recently that pyrrolidine dithiocarbamate (PDTC), an antioxidant and inhibitor of NF-kappaB activation, was protective in a rat model of acute liver failure. The aim of the present study was to examine the efficacy of PDTC in a chronic rat model of thioacetamide (TAA)-induced hepatic fibrosis.
Liver cirrhosis was induced by intraperitoneal injections of TAA (200 mg/kg) twice weekly for 12 weeks. Two groups of rats also received PDTC (either 20 or 60 mg/kg, i.p. for 12 weeks).
TAA administration induced liver cirrhosis, which was inhibited by PDTC in a dose-dependent manner. The histopathologic score of fibrosis, the spleen weight, and hepatic hydroxyproline were significantly lower in the rats treated with TAA+PDTC compared with TAA only (P<0.001). The hepatic levels of thiobarbituric acid reactive substances and protein carbonyls after 12 weeks of treatment were also lower in the rats treated with TAA+PDTC (P=0.02 and 0.01, respectively), indicating reduced oxidative stress. Immunohistochemical studies and in situ hybridization demonstrated inhibition of stellate cell (alpha smooth muscle actin positive) activation, tissue inhibitor of metalloproteinase-2, and collagen alpha1(I) gene expression in the livers of the PDTC-treated rats. As determined by Northern blot analysis, PDTC had no inhibitory effect on collagen alpha1(I) gene expression in the rat hepatic stellate cells-T6 cells in vitro.
PDTC inhibits the development of liver cirrhosis in TAA-treated rats. The mechanism of action is associated with decreased oxidative stress and hepatic necroinflammation.
核因子κB（NF-κB）激活、促炎细胞因子和活性氧被认为是肝损伤和纤维化形成的介质。我们最近发现，吡咯烷二硫代氨基甲酸盐（PDTC）作为一种抗氧化剂和NF-κB激活抑制剂，在急性肝衰竭大鼠模型中具有保护作用。本研究的目的是检测PDTC在硫代乙酰胺（TAA）诱导的慢性大鼠肝纤维化模型中的疗效。
通过每周两次腹腔注射TAA（200mg/kg），持续12周诱导肝硬化。两组大鼠也接受PDTC（20或60mg/kg，腹腔注射，持续12周）。
给予TAA可诱导肝硬化，而PDTC可呈剂量依赖性抑制该过程。与仅接受TAA治疗的大鼠相比，接受TAA+PDTC治疗的大鼠纤维化的组织病理学评分、脾脏重量和肝脏羟脯氨酸水平显著降低（P<0.001）。TAA+PDTC治疗12周后，大鼠肝脏中硫代巴比妥酸反应性物质和蛋白质羰基水平也较低（分别为P=0.02和0.01），表明氧化应激减轻。免疫组织化学研究和原位杂交显示，PDTC治疗的大鼠肝脏中星状细胞（α平滑肌肌动蛋白阳性）激活、金属蛋白酶组织抑制剂-2和胶原蛋白α1（I）基因表达受到抑制。通过Northern印迹分析确定，PDTC在体外对大鼠肝星状细胞-T6细胞中的胶原蛋白α1（I）基因表达无抑制作用。
PDTC可抑制TAA处理大鼠肝硬化的发展。其作用机制与氧化应激和肝脏坏死性炎症减轻有关。
