Immunohistochemical expression of Matrix Metalloproteinase 2 and Tissue Inhibitors of Matrix Metalloproteinase 2 in Hepatic Fibrogenesis in Dogs

Abstract

Hepatic fibrogenesis is a complex process and is due to both hypersecretion ofextracellular matrix proteins and to the inhibition of matrix degradation by the tissue inhibitors ofmatrix metalloproteinases.The present study is aiming to determine the immunohistochemical expression of MMP2and TIMP-2 in active hepatic fibrogenesis in dogs.The study was realized on 10 hepatic samples, obtained during necropsy at our faculty’sPathology department. Immunohistochemical exam was realized using antibodies against MMP2and TIMP-2In our study, MMP 2 was strongly expressed by the periseptal hepatocytes someintralobulary located hepatocytes in the regions of sinusoidal capillarization and by inflammatorycells within fibrous septae. Hepatic stellate cells and Kuppfer cells showed strong cytoplasmiclabeling, while sinusoidal endothelial cells expresed the protein slightly and inconstantly.In the present study we showed that periseptal hepatocytes and hepatic stellate cellscoexpress MMP2 and TIMP-2, in the active fibrogenesis process TIMP-2 expression beingdominant.In dogs, the main source of MMP2 and TIMP-2 are represented by the hepatocytes. Theintralobulary located hepatocytes by the secretion of TIMP-2 are involved in the sinusoidalcapillarization.