ULTRASTRUCTURAL HEPATIC ALTERATIONS IN HAMSTERS AND JIRDS AFTER EXPERIMENTAL-INFECTION WITH THE LIVER FLUKE OPISTHORCHIS-VIVERRINI

Changes in the hepatocytes of male hamsters (Mesocricetus auratus) and jirds (Meriones unguiculatus) at 220 days after experimental infectio n with the liver fluke Opisthorchis viverrini were studied by light an d electron microscopy. The hepatocytes of the control group were chara cterized by an intracellular compartmentation. A globular nucleus was located centrally. The main features of the perinuclear zone were the cisternae of the rough endoplasmic reticulum (RER) and interjacent mit ochondria, lysosomes, and peroxisomes. The peripheral cell region was dominated by glycogen fields and scattered lipid droplets, which were surrounded by anastomosing tubules of the smooth endoplasmic reticulum (SER). An immense proliferation of the SER was striking in the hepato cytes of animals infected with O. viverrini. Coincidentally, the intra cellular compartmentation disappeared. Glycogen rosettes, RER, lysosom es, and lipid droplets were distributed irregularly all over the cell, the latter being observed more frequently than in control animals. Th e nuclei showed lobe-like protrusions and were enlarged. The mitochond ria were often dumbbell-shaped and showed pathologic degenerations up to lysis. Our results resemble those of numerous investigations concer ning hepatocellular alterations caused by N-nitroso compounds. Therefo re, these observations suggest a synergistic effect for trematode infe ction and N-nitroso compounds in the pathogenesis of opisthorchiasis. The cellular alterations observed in the hepatocytes of Opisthorchis-i nfected animals together with the accumulation of intermediate filamen ts seen in the adjacent bile-duct epithelia and in the epithelium of t he gallbladder seem to indicate a disturbance of the cell metabolism a nd might be related to a neoplastic transformation.