AIMS: Cirrhotic patients commonly have a liver zinc deficiency, which may aggravate liver fibrosis due to the lack of antioxidative effects of zinc. This study examined the ability of polaprezinc, N-(3-aminopropionyl)-l-histidinato zinc, to prevent fibrosis in a rat model of thioacetamide (TAA)-induced hepatic fibrosis. MAIN METHODS: Liver cirrhosis was induced by orally administering TAA for 20 weeks. The rats were cotreated with one of the following for the last 10 weeks of TAA treatment: (1) polaprezinc (50 or 200mg/kg/day); (2) l-carnosine (155 mg/kg/day), which contained equal amounts of l-carnosine as 200mg/kg/day polaprezinc; (3) zinc sulfate (112 mg/kg/day) or (4) zinc-l-aspartic complex (317.8 mg/kg/day). Both zinc supplementations contained equal amounts of zinc as high-dose polaprezinc. KEY FINDINGS: Hepatic zinc levels fell significantly in rats treated with TAA for 20 weeks. Cotreating with high-dose polaprezinc and zinc-l-aspartic complex for 10 weeks prevented hepatic zinc loss. Hepatic hydroxyproline and tissue inhibitor of metalloproteinases-1 (TIMP-1) were significantly higher in rats treated with TAA for 20 weeks than 10 weeks, whereas polaprezinc prevented changes in these fibrosis markers and reduced hepatic transforming growth factor-β1 protein concentration, macroscopic and histologic changes. TAA caused oxidative stress-related changes in the liver that were prevented by high-dose polaprezinc and partially by zinc-l-aspartic complex. Treatment with l-carnosine, low-dose polaprezinc or zinc sulfate for 10 weeks did not affect liver fibrosis progression or oxidative stress-related changes. SIGNIFICANCE: Polaprezinc may prevent ongoing fibrosis by preventing zinc depletion, oxidative stress and fibrosis markers in cirrhotic livers.
AIMS: Cirrhotic patients commonly have a liver zinc deficiency, which may aggravate liver fibrosis due to the lack of antioxidative effects of zinc. This study examined the ability of polaprezinc, N-(3-aminopropionyl)-l-histidinato zinc, to prevent fibrosis in a rat model of thioacetamide (TAA)-induced hepatic fibrosis. MAIN METHODS:Liver cirrhosis was induced by orally administering TAA for 20 weeks. The rats were cotreated with one of the following for the last 10 weeks of TAA treatment: (1) polaprezinc (50 or 200mg/kg/day); (2) l-carnosine (155 mg/kg/day), which contained equal amounts of l-carnosine as 200mg/kg/day polaprezinc; (3) zinc sulfate (112 mg/kg/day) or (4) zinc-l-aspartic complex (317.8 mg/kg/day). Both zinc supplementations contained equal amounts of zinc as high-dose polaprezinc. KEY FINDINGS: Hepatic zinc levels fell significantly in rats treated with TAA for 20 weeks. Cotreating with high-dose polaprezinc and zinc-l-aspartic complex for 10 weeks prevented hepatic zinc loss. Hepatic hydroxyproline and tissue inhibitor of metalloproteinases-1 (TIMP-1) were significantly higher in rats treated with TAA for 20 weeks than 10 weeks, whereas polaprezinc prevented changes in these fibrosis markers and reduced hepatic transforming growth factor-β1 protein concentration, macroscopic and histologic changes. TAA caused oxidative stress-related changes in the liver that were prevented by high-dose polaprezinc and partially by zinc-l-aspartic complex. Treatment with l-carnosine, low-dose polaprezinc or zinc sulfate for 10 weeks did not affect liver fibrosis progression or oxidative stress-related changes. SIGNIFICANCE: Polaprezinc may prevent ongoing fibrosis by preventing zinc depletion, oxidative stress and fibrosis markers in cirrhotic livers.