Carbon tetrachloride and dimethynitrosamine, both similar potent hepatotoxic agents, agents, affect the hepatic lobules with marked central necrosis, and their hepatotoxic actions are influenced by the enzyme system(dru-gmetabolizing enzyme) produced in the smooth surfaced endoplasmic reticulum in the hepatic cells.
In order to study the cytopathological effects of carbon tetrachloride pretreatment on the acute hepatotoxic changes induced by dimethynitroeamine, the control animals, the SprasgueDawley rats were intoxicated with 40mg/kg of dimethylnitrosamine by intraperitoneal´ injection and the experimental animals were pretreated with 0. 4, 0. 6, 0. 8, 1. 0 and 1.2m1/ kg of carbon tetrachloride before dimethylnitrosamine intoxication.
The mortality and cytopathological changes in the control and experimental groups were as follows:
1. Mortality in the control group was 33.3%, and those of experimental groups pretreated with 0. 4, 0. 6, 0. 8, 1. 0 and 1.2m1 of carbon tetrachloride were 20.8%, 0.0%, 12.5%, 62.5% and 70.8%, respectively. The mortality indicated the lowest, 0.6m1 group, and the highest, 1.2m1 group.
2. The necrocytotoxic changes of the liver showed moderate to marked in the control group, and those of the experimental group showed the most highest in the 1.2m1 and 1.Oml groups, and the lowest in the 0.6m1 group.
3. The mitoses of the hepatic cells were rare from 52 to 96 experimental hours in the control group, whereas those of the experimental groups showed more numerous and active from 24 to 48 experimental hours in the 0.6m1 group.
Those of 1.Oml and 1.2m1 group showed moderate in number and appeared later after 48Texperimental hours.
4. The regenerative change of the sinus lining cells in the hepatic lobules and reconstruction of the hepatic lobules were faintly achieved after 72 experimental hours in the
control group, whereas those of the experimental groups showed prominent and active from early experimental day in the 0.6m1, 0.4m1 and 0.8m1 groups, and showed milder and appeared later in both 1. Oml and 1.2m1 groups.
5. The above results suggest that 0.6m1 of carbon tetrachloride pretreatment protects against the necrocytotoxic action of dimethylnitrosamine hepatotoxicity and promotes the regenerative activity of hepatic lobules after acute dimethylnitrosamine intoxication.
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