  The liver of reptiles is considered an important study model for the
interaction between environment and hepatic tissue. Little is known about the
histology of the liver of reptiles. The aim of the current study was to
elucidate the histological architecture of the liver of the Nile monitor
(Varanus niloticus). Liver fragments from the Nile monitor were collected in
the summer season and processed for the light and electron microscopy. The
liver of the Nile monitor was bi-lobed and the right lobe was found to be
larger than the left lobe. Histological examination revealed indistinct
lobulation of the liver, and the central vein, sinusoids and portal area were
haphazardly organized. The hepatic parenchyma consisted of hepatocytes arranged
in glandular-like alveoli or tubules separated by a network of twisted
capillary sinusoids. The hepatocytes were polyhedral in shape with vacuolated
cytoplasm and the nucleus was single rounded, eccentric, large and vesicular
with a distinct nucleolus. The hepatocytes contained numerous lipid droplets,
abundant glycogen granules and well-developed RER and mitochondria. The
hepatocytes appeared to secrete into the bile canaliculi through the
disintegration of their dark cytoplasm into the bile canaliculi. The space of
Disse separating between the hepatocytes and sinusoids contained many recesses.
The portal area contained branches of the portal vein, hepatic artery, bile
duct and lymphatic vessels embedded in a connective tissue. Some
non-parenchymal cells were described such as Kupffer cells, heterophils,
melano-macrophages, intercalated cells, myofibroblasts in addition to the
endothelium of the sinusoids. This is the first report about the histological
structure of the liver of the Egyptian Nile monitor. The result presented here
should be considered a baseline knowledge to compare with the pathological
affections of the liver in this species.
