Kupffer cell structure in the juvenile Nile crocodile,Crocodylus niloticus

Abstract

The morphology of Kupffer cells was examined in the liver of the juvenile Nile crocodile using light microscopy and transmission electron microscopy. Pleomorphic Kupffer cells were located in the sinusoids, in the space of Disse, in the hepatic parenchyma and often connected adjacent sinusoids. The cell surfaces were irregular due to the presence of filopodia and lamelliapodia with phagocytosis of white blood cells, red blood cells and thrombocytes being evident. The cells were in close contact with endothelial cells and pit cells in the sinusoidal lumen and with stellate cells in the space of Disse. The cytoplasm contained large phagosomes comprising a combination of ceroid pigment, melanosomes and siderosomes. The nuclei were often indented and eccentrically placed due to the presence of the phagosomes. Conspicuous clusters of membrane-bound tubular organelles with a filamentous or crystalline interior were observed in the cytoplasm. The clusters were sometimes separated into smaller groups around phagosomes. A clear zone existed between the limiting membrane and the interior of these tubular organelles with the electron-dense interior profiles being, respectively, circular, angular or divided. The tubular organelles have not previously been described in Kupffer cells and possibly represent lysosomes with specialized functions. Mitochondria, microtubules, Golgi profiles, granular and smooth endoplasmic reticulum, and a few cytoplasmic lipid droplets were also present. The presence of the tubular organelles and the occurrence of the Kupffer cells in different locations in the liver of the juvenile Nile crocodile are indicative of particularly active and mobile cells.

Structural and immunohistochemical analysis of the cellular compositions of the liver of molly fish (Poecilia sphenops), focusing on its immune role

“…The findings of this study support the notion that that Kupffer cells play a vital role in autophagy and phagocytosis. These suggestions are in agreement with van Wilpe and Groenewald [ 30 ], who stated that Kupffer cells play a critical role in elimination of degenerated blood cells, degradation of hemoglobin, and removal of toxic materials.…”

“…When present, they show a strong phagocytic activity [ 28 ]. Kupffer cells were recognized in spotted pimelodus [ 29 ] and in Juvenile crocodile [ 30 ]. However, they were not observed in the liver of Kareius bicoloratus [ 31 ] or Salmo trutta fario [ 10 ].…”

Comparative Histological Study of Parenchymal Arrangements in Three Orders of Reptilian Livers

“…Aggregations of pigmented cells, termed MMs, have been found in the livers of some fishes [8,9], amphibians [10][11][12][13], and reptiles [14][15][16][17]. Previous studies demonstrated that the pigmented cells of amphibian livers are cells belonging to the macrophage lineage of Kupffer cells [23][24][25] as well as the MMs centers of fishes [19,26,27].…”

“…In the Nile crocodile [17] and other reptiles [29], large yellow-brown cytoplasmic phagosomes were detected in Kupffer cells located in hepatic lobules.…”

“…In heterothermic vertebrates, aggregations of pigmented cells termed melanomacrophages (MMs) have been identified in the livers of some fishes [8,9], amphibians [10][11][12][13], and reptiles [14][15][16][17]. Extracutaneous melanin-containing cells have been detected in various tissues and organs such as the liver, spleen, kidney, and lungs [9,18,19].…”