Original Article Dose-Dependent Antifibrotic Effect of Chrysin on Regression of Liver Fibrosis: The Role in Extracellular Matrix Remodeling Cornel Balta 1 , Alina Ciceu 1 , Hildegard Herman 1 , Marcel Rosu 1 , Oana Maria Boldura 2 , and Anca Hermenean 1,3 Abstract Liver fibrosis represents an overaccumulation of extracellular matrix (ECM). This study was designed to investigate the effect of chrysin on established ECM overproduction in carbon tetrachloride (CCl 4 ) mouse liver fibrosis. Experimental fibrosis was induced by intraperitoneal injection of 2 mL/kg CCl 4 twice a week, for 7 weeks. Mice were orally treated with 3 doses of chrysin (5,7-dihydroxyflavone). For the assessment of the spontaneous reversion of fibrosis, CCl 4 -treated mice were investigated after 2 weeks of recovery time. Silymarin was used as a standard of liver protection. In fibrotic livers, the results showed the upre- gulation of collagen I (Col I) and tissue inhibitors of metalloproteinase 1 (TIMP-1) and modulation of matrix metalloproteinases (MMPs), which led to an altered ECM enriched in Col, confirmed as well by electron microscopy investigations. Treatment with chrysin significantly reduced ultrastructural changes, downregulated Col I, and restored TIMP-1/MMP balance, whereas in the group observed for the spontaneous regression of fibrosis, they remained in the same pattern with fibrotic livers. In this study, we have shown chrysin efficacy to attenuate dose-dependent CCl 4 -stimulated liver ECM accumulation by regulation of MMP/TIMP imbalance and inhibition of Col production. We have shown the dose-dependent chrysin efficiency in attenuation of CCl4-induced liver ECM accumulation by regulation of MMP/TIMP imbalance and inhibition of Col production. Our findings suggest that chrysin oral administration may introduce a new strategy for treating liver fibrosis in humans. Keywords liver fibrosis, chrysin, ECM, MMPs, TIMP-1, collagen Introduction Hepatic fibrosis is a common wound healing response to chronic liver injury, 1 involving extra deposition of extracellular matrix (ECM) proteins. 2,3 The fibrotic ECM is composed of collagens, especially type I and III collagens, 2 structural gly- coproteins, proteoglycans, and hyaluronan. 4,5 In the liver, acti- vated hepatic stellate cells (HSCs) and myofibroblast (MF) with overlapping phenotypes deposit the majority of the fibro- tic ECM. The main scar proteins produced by these fibrogenic effector cells are collagens, especially collagen type I, but sev- eral other proteins play a role in fibrotic matrix organization. 6 Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are the main regulators of ECM turnover in hepatic fibrosis. 7 The liver injury disturbs the TIMP/MMP balance and overexpresses TIMPs, contributing to ECM deposition and fibrosis progress. 8 Matrix metalloproteinases are calcium-dependent zinc- containing endoproteinases, produced by connective and inflammatory cells. 9 So far, 23 MMPs have been discovered in humans, 10 from which MMP-1, MMP-2, MMP-3, MMP-9, MMP-11, and MMP-13 are constitutively expressed in normal livers 7 by parenchymal cells such as hepatocytes or nonpar- enchymal cells such as HSCs, Kupffer cells, neutrophils, and 1 Institute of Life Sciences, “Vasile Goldis” Western University of Arad, Arad, Romania 2 Department of Chemistry, Biochemistry and Molecular Biology, Faculty of Veterinary Medicine, Banat University of Agricultural Sciences and Veterinary Medicine “King Mihai I of Romania,” Timisoara, Romania 3 Department of Histology, Faculty of Medicine, Pharmacy and Dentistry, “Vasile Goldis” Western University of Arad, Arad, Romania Received 19 April 2018; received revised 04 June 2018; accepted 12 June 2018 Corresponding Author: Anca Hermenean, Department of Histology, Faculty of Medicine, Pharmacy and Dentistry, “Vasile Goldis” Western University of Arad, Arad, Romania. Email: anca.hermenean@gmail.com Dose-Response: An International Journal July-September 2018:1-8 ª The Author(s) 2018 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/1559325818789835 journals.sagepub.com/home/dos Creative Commons Non Commercial CC BY-NC: This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (http://www.creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).