Descrições macro e microestruturais do fígado de zebrafish (Danio rerio)

Abstract

Liver is an essential organ and performs a number of vital activities such as metabolism, synthesis and storage. This research aimed to describe macroscopically and microscopically the liver of zebrafish and the liver temporal changes in thirteen weeks. We used forty six (46) fishes Danio rerio, adults, twenty seven (27) females and nineteen (19) males. Seven fishes were euthanized for macroscopic analyses and three fishes were euthanized weekly for thirteen weeks for microscopic analyses. It was conducted routine histological technique and the slides were stained with Hematoxylin/Eosin and periodic acid-Schiff (PAS). Weekly, it was determined volumetric (Vv(h)) and numerical (Nv(h)) densities of hepatocytes and intensity of vacuolization. The liver was located in the coelomic cavity ventrally to swim bladder, showed slightly brownish and was divided into three hepatic lobes. Microscopically, the liver consisted of hepatocytes arranged as a double cell layer around sinusoids. The staining of the cytoplasm of hepatocytes in males was more eosinophilic and basophilic than in females. Formation of portal triads and phagocytic cells were not found. The gallbladder had transitional epithelium and biliary ducts were composed by simple cubic epithelium. The volume and numerical density of hepatocytes during thirteen weeks showed no statistical difference, but the correlation between these parameters was positive. The vacuolization was due glycogen. The zebrafish liver has macro and microstructural features and quantitatively has great ability to adapt in volume and number of hepatocytes in response to the physiological needs.