PATHOHISTOLOGICAL STUDIES ON THE LIVER FIBROSIS EXPERIMENTALLY INDUCED IN RABBITS

Abstract

1. In the present experiment, diethyl-paranitrophenyl-thiophosphate was administered on rabbits by subcutaneous injections repeated twice per week in different doses of 2, 4, 8 and 12 mg/kg body weight. Then, the animal were divided into groups of acute, subacute, chronic, fatal and survived (120 to 200 days) and investigations were made on the morphological changes produced in the liver.
2. On analysing hepatic lesions, spleen which has a close functional relationship with the liver was also investigated, and thus the presence of highly advanced hemosiderosis and fibrosis were recognized.
3. Morphological changes observed in the liver were the vacuolar degeneration, fatty degeneration and focal necrosis of the hepatic parenchymatous cells. These findings were in agreement with the disappearance of the reticular fibers or PAS stainable fibers of the hepatic capillary and were dominant in the periphery of the hepatic lobule.,
4. Glycogen content of the hepatic cell was found to have reduced parallel to the degenerative changes of the parenchymatous cells and the capillary wall.
5. Appearance of the leisons in hepatic interstitium was first recognized in the loosening of vascular muscle layer accompanied by gradual fiber production of the degenerative lesions in the periphery of hepatic lobule.
6. This hepato-lobular centric fibrosis was mild but was in good agreement with the advanced myocardiac damages suggesting the importance of the influence of cardiac disorders.
7. Marked hemosiderosis was recognized on the hepatic interstitium, perilobular hepatic cells, Kupper's stellate cells and partly on the hepatic cells in the center of lobule as well as spleen and this finding was especially strong in fatal cases. Intensity of hemosiderosis, however, was not in agreement with the findings of hepatic fibrosis.
8. Varying degenerative lesions of hepatic parenchyma, hemosiderosis and hepatic fibrosis stated above are considered to be the morphological expression of the disturbances of vascular system and the metabolism of hepatic parenchymatous cell caused by the hypoxydosis due to the disturbance of radox enzym by the administration of diethyl-paranitrophenyl-thiophosphate.
9. Interstitial fibrosis of the present experiment characterized by the increase of reticular fibers appeared to be closely related with the mechanism of hydropic cirrhosis and, moreover, there was a strong resemblance between the irregular production of reticular fibers in the periphery of hepatic lobule and angiohematotoxic cirrhosis accompaning the proliferation of sinus endothelium.