CELLULAR MECHANISMS OF CIRRHOTIC RAT LIVER REGENERATION. II. PROLIFERATION, POLYPLOIDIZATION AND
HYPERTROPHY AFTER PARTIAL HEPATECTOMY
G. A. Sakuta, B. N. Kudryavlsev
Institute of Cytology, RAS, St. Petersburg, Russia;
e-mail: sakula@mail.cytspb.rssi.ru
Using cytofluorhnetry and absorptional cytophotometry, hepatocyte DNA and total protein contents were measured
in intact and cirrhotic rats in 1, 3 and 6 months after partial hepatectomy (PH). It has been found that within one month of
intact rat liver regeneration the level of hepatocyte ploidy rised by 25 % to remain elevated for the next 6 months. This was
due mainly to reducing the number of cells with diploid nuclei (2c - 2-fold, 2c x 2 - 6.6-fold) and to rising the
number of octaploid hepatocytes. In cirrhotic animals the ploidy level in hepatocy-tes increased in 3 months after PH, and
decreased by 15 % in 6 months. The number of hepatocytes with diploid nuclei (2c and 2c x 2) increased within
3-6 months in both control and cirrhotic rats. The protein content per diploid hepatocyte rised by 30 % within 3-6 months of
liver regeneration after PH. Special calculations have shown that within 3 months after PH the increase in the liver mass of
control and cirrhotic rats was due completely to hepatocyte DNA synthesis, i. e. proliferation and polyploidization. Within the
next 3 months of liver regeneration after PH, the contribution of polyploidization to liver mass increase was negative because
of depolyploidization of liver parenchyma cell population. At this time hypertrophy was the main process determining the liver
mass increase.
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