The anti-fibrotic effect of liver growth factor is associated with decreased intrahepatic levels of matrix metalloproteinases 2 and 9 and transforming growth factor beta 1 in bile duct-ligated rats
Juan J. Díaz-Gil1, Carmelo García-Monzón2, Carmen Rúa3, Paloma Martín-Sanz4, Rosa M. Cereceda1, María E. Miquilena-Colina2, Celia Machín3, Amalia Fernández-Martínez4 and Rafael García-Cañero1
1Department of Experimental Biochemistry, Hospital Puerta de Hierro, Madrid, Spain, 2Laboratory of Experimental Hepatology, Hospital Santa Cristina, Madrid, Spain, 3Department of Cellular Biology, Faculty of Biological Sciences, UCM, Madrid, Spain and 4Centro Investigaciones Biológicas, CSIC, Madrid, Spain.
Offprint requests to: Juan J. Díaz-Gil, PhD, Servicio de Bioquímica Experimental, Hospital Universitario Puerta de Hierro, c/ S. Martín de Porres, 4, 28035 Madrid, Spain. e-mail: jdiaz.hpth@salud.madrid.org
Summary. Liver growth factor (LGF), a mitogen for liver cells, behaves as an anti-fibrotic agent even in extrahepatic sites, but its mechanistic basis is unknown. We aimed to determine the intrahepatic expression pattern of key modulators of liver fibrosis in bile duct-ligated rats (BDL) after injection of LGF. BDL rats received either LGF (4.5 µg/ratXdose, two doses/week, at time 0 or 2 or 5w after operation, depending on the group (BDL+LGF groups, n=20) or saline (BDL+S groups, n=20). Groups were compared in terms of fibrosis (histomorphometry), liver function (aminopyrine breath test), matrix metalloproteinases MMP-2 and MMP-9, transforming growth factor beta 1 (TGF-ß1) and liver endoglin content (Western blotting), and serum tissue inhibitor of metalloproteinases 1 (TIMP-1) levels (ELISA). In BDL+LGF rats, the fibrotic index was significantly lower at 5w, p=0.006, and at 8w, p=0.04, than in BDL+S rats. Liver function values in BDL+LGF rats were higher than those obtained in BDL+S rats (80% at 5w and 79% at 8w, versus 38% and 29%, p<0.01, taking healthy controls as 100%). Notably, in BDL+LGF rats the intrahepatic expression levels of both MMPs were lower at 2w (MMP-2, p=0.03; MMP-9, p=0.05) and 5w (MMP-2, p=0.05, MMP-9, p=0.04). In addition, the hepatic TGF-ß1 level in BDL+LGF rats was lower at 2w (36%, p=0.008), 5w (50%) and 8wk (37%), whereas intrahepatic endoglin expression remained constant in all BDL rats studied. LGF ameliorates liver fibrosis and improves liver function in BDL rats. The LGF-induced anti-fibrotic effect is associated with a decreased hepatic level of MMP-2, MMP-9 and TGF-ß1 in fibrotic rats. Histol Histopathol 23, 583-591 (2008)
Key words: Bile duct-ligated rats, Cirrhosis, Fibrosis, Regeneration
DOI: 10.14670/HH-23.583