Francesca Maria Trovato1, Paola Castrogiovanni2, Marta Anna Szychlinska2, Francesco Purrello1, Giuseppe Musumeci3. 1. Department of Clinical and Experimental Medicine, Internal Medicine Unit, University of Catania, Catania, Italy. 2. Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, University of Catania, Catania, Italy. 3. Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology Section, University of Catania, Catania, Italy. g.musumeci@unict.it.
Abstract
BACKGROUND AND AIM: Western high-fat diet is related to metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Decreased levels of Vitamin D (VitD) and IGF-1 and their mutual relationship were also reported. We aimed to evaluate whether different dietary profiles, containing or not VitD, may exert different effects on liver tissue. METHODS: Twenty-eight male rats were fed for 10 weeks by different dietary regimens: R, regular diet; R-DS and R-DR, regular diet with respectively VitD supplementation (DS) and restriction (DR); HFB-DS and HFB-DR (41% energy from fat), high fat (butter) diet; HFEVO-DS and HFEVO-DR (41% energy from fat), high fat (Extra-virgin olive oil-EVO) diet. Severity of NAFLD was assessed by NAFLD Activity Score. Collagen type I, IL-1beta, VitD-receptor, DKK-1 and IGF1 expressions were evaluated by immunohistochemistry. RESULTS: All samples showed a NAS between 0 and 2 considered not diagnostic of steatohepatitis. Collagen I, although weakly expressed, was statistically greater in HFB-DS and HFB-DR groups. IL-1 was mostly expressed in rats fed with HFBs and HFEVOs and R-DR, and almost absent in R and R-DS diets. IGF-1 and DKK-1 were reduced in HFBs and HFEVOs diets and in particular in DR groups. CONCLUSIONS: A short-term high-fat diet could damage liver tissue in terms of inflammation and collagen I deposition, setting the basis for the subsequent steatohepatitis, still not identifiable anatomopathologically. Vitamin D restriction increases inflammation and reduces the expression of IGF-1 in the liver, worsening the fat-induced changing. EVOO seems be protective against the collagen I production.
BACKGROUND AND AIM: Western high-fat diet is related to metabolic syndrome and non-alcoholic fatty liver disease (NAFLD). Decreased levels of Vitamin D (VitD) and IGF-1 and their mutual relationship were also reported. We aimed to evaluate whether different dietary profiles, containing or not VitD, may exert different effects on liver tissue. METHODS: Twenty-eight male rats were fed for 10 weeks by different dietary regimens: R, regular diet; R-DS and R-DR, regular diet with respectively VitD supplementation (DS) and restriction (DR); HFB-DS and HFB-DR (41% energy from fat), high fat (butter) diet; HFEVO-DS and HFEVO-DR (41% energy from fat), high fat (Extra-virgin olive oil-EVO) diet. Severity of NAFLD was assessed by NAFLD Activity Score. Collagen type I, IL-1beta, VitD-receptor, DKK-1 and IGF1 expressions were evaluated by immunohistochemistry. RESULTS: All samples showed a NAS between 0 and 2 considered not diagnostic of steatohepatitis. Collagen I, although weakly expressed, was statistically greater in HFB-DS and HFB-DR groups. IL-1 was mostly expressed in rats fed with HFBs and HFEVOs and R-DR, and almost absent in R and R-DS diets. IGF-1 and DKK-1 were reduced in HFBs and HFEVOs diets and in particular in DR groups. CONCLUSIONS: A short-term high-fat diet could damage liver tissue in terms of inflammation and collagen I deposition, setting the basis for the subsequent steatohepatitis, still not identifiable anatomopathologically. Vitamin D restriction increases inflammation and reduces the expression of IGF-1 in the liver, worsening the fat-induced changing. EVOO seems be protective against the collagen I production.