Liver of the brown trout, Salmo trutta (Teleostei, Salmonidae): A stereological study at light and electron microscopic levels

Abstract

Background: A quantitative study was undertaken for the first time on the normal liver of male and female 2-year-old brown trout, Salmo trutta.Methods: Liver was fixed by controlled perfusion. Organ-level morphometry provided weight and volume. A two-stage stereological approach was performed at light and electron microscopy levels. Systematic sampling and point-counting morphometry were used for estimating the relative volumes of the structural compartments. Total absolute volumes of these components were obtained by multiplying each volume density by the volume of its reference space.Results: Liver volume was 3,423.6 mm 3 for males and 3,657.4 mm 3 for females. Parenchyma accounted for 95% of hepatic volume. Veins and bile ducts occupied, respectively, 76% and 17% of the stroma, whereas arteries, connective tissue, and melanomacrophages together composed only 6%. Hepatocytes occupied 88% of the parenchyma. Nonhepatocytic cells (endothelium, biliary epithelial cells, Ito cells, and macrophages) composed 4% of the parenchyma, the capillary lumen 6%, and other spaces (Disse space, canaliculi, and lumina of preductules and ductules) composed 2%. Significant sexual differences were found: (1) Females showed a greater parenchymal volume density (0.85% vs. 0.35%) and absolute volume (29.5 mm 2 vs. 11.7 mm 3 ) of Ito cells; (2) macrophages of females also presented a greater parenchymal volume density (0.94% vs. 0.46%), but not absolute volume.Conclusions: The need to analyze both relative and absolute stereological data was stressed. Similarities and differences were detected between brown trout and other species (fishes and mammals); the findings suggest that, despite architectural differences, some quantitative parameters of liver microanatomy were retained during phylogeny. Factors mediating sexual differences in Ito cells and macrophages were discussed and the need for further studies was highlighted. Anat.

A genetic screen in zebrafish identifies the mutantsvps18, nf2andfoie grasas models of liver disease

“…Teleosts do not appear to have a canal of Hering, but instead the canaliculi empty directly into the lumen of preductules, which are formed by biliary pre-ductal epithelial cells (PDEC), a specialized cell of the intrahepatic biliary tree in teleosts (Hinton and Pool, 1976;Rocha et al, 1994). PDECs form the lumen of the pre-ductule by wrapping around themselves, analogous to capillary formation by endothelial cells (Hinton and Couch, 1998;Hinton and Pool, 1976;Rocha et al, 1994).…”

“…This provides the opportunity to carry out an embryonic screen to identify mutants that are defective in either liver development or function, or both. Third, baring minor differences, the anatomy, function, organization and cellular composition of adult zebrafish and mammalian livers are virtually the same (Hinton and Couch, 1998;Rocha et al, 1994;Wallace and Pack, 2003), as is the histopathology of fatty liver (steatosis), cholestasis and neoplasia (Amatruda et al, 2002;Spitsbergen et al, 2000) (J. Glickman, personal communication), allowing direct comparison between zebrafish and mammalian liver disease processes. Indeed, recent work has demonstrated that genes that underlie Alagille Syndrome, a pediatric disorder that results in a paucity of intrahepatic bile ducts, among other defects, play an important role in zebrafish biliary development .…”

Morphology and Histochemistry of the Liver of Carnivorous Fish Hemisorubim platyrhynchos

“…It is considered a target organ for the study of interactions among environmental factors and structure and/or hepatic functions (Bruslé & Anadon). In this sense, the morphological characteristics of the liver have been associated with physiological status in fish (Caballero et al, 1999) and used as an indicator of environmental quality (Rocha et al, 1994;Al-Youseif et al, 2000;Gochfeld, 2003).…”

Histological structures of the accessory glands of the digestive system in adult farmed African catfish (Clarias gariepinus B.)

“…The diffuse to radial arrangement has been reported in other teleosts [9,22]. This diffuse arrangement may help in the rate of liver functions especially that of detoxification and metabolite storage, as more cells will be reached faster in an aquatic environment that ingestion of food and water is very frequent.…”