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Hepatic stellate cells (HSCs) play a significant role in hepatic fibrogenesis. In the following study we described the distribution of cells that express alpha-smooth muscle actin (α-SMA) and desmin in the cat liver with various degrees of fibrosis, as well as the significance of hepatic stellate cells and portal myofibroblasts in the genesis of fibrosis in cats with polycistic kidney disease. Liver samples from 15 necropsied Persian cats were examined microscopically, using H&E and Masson-trichrom methods and immunohistology for α-SMA and desmin. Liver fibrosis was confirmed in cats with terminal stage of chronic cholangiohepatitis and it was characterized by connective tissue septa which divide the liver parenchyma into irregular lobuli. Inflammation in the cat liver is connected with the activation of periductal myofibroblasts. The intensity of immunopositivity of perisinusoidal HSCs to α-SMA and desmin varied depending on the degree of fibrosis and was the strongest in livers of cats with cirrhosis., U ovom radu je opisana distribucija ćelija koje eksprimiraju α-glatkomišićni aktin (α-SMA) i dezmin u jetri mačaka sa različitim stadijumom fibroze, kao i značaj ovih ćelija u razvoju fibroze, kod mačaka sa policističnim bubrezima. Mikroskopski su ispitani uzorci jetre od 15 obdukovanih persijskih mačaka, korišćenjem HE i Mason-trihromnog bojenja i imunohistohemijski na α-SMA i dezmin. Fibroza jetre potvrđena je kod mačaka sa terminalnim stadijumom hroničnog holangiohepatitisa i odlikovala se prisustvom vezivno-tkivnih septi koje dele parenhim na nejednake lobuluse. Inflamacija u jetri mačaka u vezi je sa aktivacijom periduktalnih miofibroblasta. Intenzitet imunohistohemijske reakcije perisinusoidnih HSCs na α-SMA i dezmin razlikovala se od stepena fibroze i bio je najjači u jetri mačaka sa cirozom.

In this work, 36 canine livers with fibrosis were examined. Based on the degree of fibrosis, the livers were classified into three groups: 1- mild portal fibrosis; 2- moderate portal fibrosis with mild periportal and septal fibrosis; 3- severe portal fibrosis with marked periportal and septal fibrosis or cirrhosis. Normal liver sections obtained from five dogs with no evidence of infectious, neoplastic, or cardiovascular diseases were used as controls. The degree of fibrosis was evaluated on liver sections stained according to Masson's trichrome method. It was proved using an immunohistochemical method that HSC and periductal myofibroblasts are immunoreactive to desmin, vimentin and α-SMA. Desmin, vimentin and α-SMA positive cells in the portal triad were significantly more numerous in dogs with fibrosis of the third degree than in the controls or all other examined livers. The density of α- SMA, vimentin and desmin-positive cells in the portal triad was in correlation with the degree of fibrosis, which cannot be said for HSC. These results suggest that portal myofibroblasts have a significant role in the process of liver fibrosis in dogs., U ovom radu su prikazani rezultati ispitivanja 36 uzoraka tkiva jetre sa znacima fibroze, poreklom od pasa. Na osnovu stepena fibroze, uzorci su klasifikovani u tri grupe: 1 - blaga portalna fibroza; 2 - umerena portalna fibroza sa blagom periportalnom i septalnom fibrozom; 3 - teška portalna fibroza sa izraženom periportalnom i septalnom fibrozom ili cirozom. Kao kontrola su korišćeni uzorci tkiva jetre dobijeni od pet pasa bez znakova infekcije, neoplazije i kardiovaskularnih bolesti. Evaluacija stepena fibroze je urađena na isečcima jetre bojenim po Masson trihromnoj metodi. Imunohistohemijskom metodom je pokazano da su HSC i periduktalni miofibroblasti imunoreaktivni na dezmin, vimentin i α-SMA. Dezmin, vimentin i α-SMA, pozitivne ćelije u portalnoj trijadi bile su značajno brojnije kod pasa sa fibrozom trećeg stepena u odnosu na kontrolu i na sve druge ispitivane uzorke tkiva jetre. Gustina α-SMA, vimentin i dezmin pozitivnih ćelija u portalnoj trijadi je bila u korelaciji sa stepenom fibroze, što se ne može reći i za HSC. Ovi rezultati sugerišu da portalni miofibroblasti imaju značajnu ulogu u procesu fibroze jetre kod pasa.