Induced hypothyroidism accelerates the regression of liver fibrosis in rats

Rafael Bruck*, Sigal Weiss, Alexandra Traister, Isabel Zvibel, Hussein Aeed, Zamir Halpern, Ran Oren

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


Background and Aim: It has been shown in previous studies that hypothyroidism prevents the development of liver fibrosis in bile duct ligated rats and in rats chronically treated with thioacetamide (TAA). In recent years, regression of liver fibrosis (occurring spontaneously or during treatment) has been demonstrated in rodent models such as bile duct ligation and CCl 4 administration. Therefore, in the present study, the potential therapeutic effect of hypothyroidism on liver fibrosis was investigated. Methods: Liver fibrosis was induced in rats by administration of TAA (200 mg/kg, i.p., twice weekly) for 12 weeks. Hypothyroidism was then induced by either methimazole (0.04%) or propylthiouracil (0.05%) administered in drinking water for 8 weeks. Control euthyroid rats received normal drinking water. Hypothyroidism was confirmed by a significant elevation of serum thyroid-stimulating hormone levels. Results: Eight weeks after the cessation of TAA administration, spleen weight, histological score of liver fibrosis, and hepatic hydroxyproline content were significantly lower in both groups of hypothyroid rats as compared to euthyroid controls (P < 0.001). In vitro studies using the rat hepatic stellate cell line HSC-T6 using northern blot analysis and zymography, respectively, showed that high concentrations of triiodotyronine (T3) enhanced transforming growth factor (TGF)-β-induced collagen I gene expression, and reduced metalloproteinase (MMP)-2 secretion, implying that reducing the levels of T3 may contribute to resolution of fibrosis. Additionally, low T3 concentration inhibited HSC-T6 proliferation. Conclusion: Pharmacologically induced hypothyroidism accelerates the resolution of liver fibrosis in rats. This beneficial effect may in part be due to prevention of T3-induced stimulation of collagen synthesis and reduction of MMP-2 secretion.

Original languageEnglish
Pages (from-to)2189-2194
Number of pages6
JournalJournal of Gastroenterology and Hepatology (Australia)
Issue number12
StatePublished - Dec 2007


  • Collagen
  • Fibrosis
  • Hypothyroidism


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