STRUCTURAL CHANGES IN RATS' LIVER DURING THE FIRST 2 WEEKS FOLLOWING 2/3 PARTIAL HEPATECTOMY.

Aim of study - Investigation of changes in hepatocyte size and shape and architecture of the sinusoidal network in 2-week dynamics after resection 2/3 of the liver. The experiments were performed on 16 adult male Wistar rats weighing 190-200 grams who underwent 2/3 resection of liver, while a resected portion of the liver of the same rat was considered as a control. We examined liver tissue by histological, immunohistochemical, morphometrical methods, and the architecture of the sinusoidal capillary network by electron microscopy of corrosion casts. The study was conducted in 24 hours, 48 hours, 96 hours, 1 week, and 2 weeks after surgery. The shape and size of the hepatocytes in the first and third zones of the liver acinus change with the term of the experiment. With changes in the shape and size of hepatocytes, new intercellular connections are formed, including with the involvement of atypical membrane protrusions of deformed neighboring hepatocytes. One week after regeneration, electron microscopic examination of corrosion casts reveals a network of sinusoids that spatially define lobules of different shapes and sizes, including those that appear to be a combination of two "normal" lobules. Superficial sinusoids are often markedly dilated (up to 25 μm). In addition, small-diameter (6-7μm) sinusoidal casts with a rough surface and small bud-shaped protrusions are observed in some areas, giving the line of this a zigzag shape. The existence of hepatic vein tributaries and associated with them large sinusoids, found In single areas, reveals the characteristic feature of vascular sprouting. Based on the data obtained, it can be assumed that despite the recovery of liver mass, the regeneration process is not complete. Regenerated liver undergoes a permanent process of transformation of hepatocytes' shape and size, as well as the transformation of the vascular network, which is the basis for changes in the spatial architecture of the liver lobules.