Malathin (0,0-dimethyl 5-[1,2 dicarboethoxyethyl] dithiophosphate) is one of the organic phosphorus compounds and has been widely used as an insecticide.
It is well known that the organophosphorus compounds inactivate an enzyme, cholinesterase, and resultant accumulation of acetylcholine effects on a pattern of cholinergic stimulation.
Present study has demonstrated the hepatotoxicity caused by malathion, an organophosphorus compound, observing the ultrastructural changes in the cytoplasmic organelles of hepatocytes in mice.
The experimental animals were given 0.2m1 of malathion diluted in olive oil (100mg/kg) by intraperitoneal injection.
The animals of control group were killed at 6 hours after olive oil treatment, and the animals of the experimental groups were killed at 12, 24 and 36 hours after ad-ministration of malathion, respectively.
The specimens obtained from the left anterior lobes of the liver were stained with uranyl acetate and lead citrate double contrast methods and observed with JEM 100B model electron microscope.
The cytoplasmic organelles of hepatocyte in malathion trated mice showed the fallowing significant changes.
1) A slight morphological changes such as dilatation, sacculation and fragementa-tion of the cisternae of rough endoplasmic reticulum associated with detachment of membrane-bound ribosomes and disaggregation of the free ribosomes are recognized.
2) Primary lysosomes were increased in number and formation of secondary lysosomes (autophagic vaculoes and residual bodies) were observed.
3) The smooth endoltasmic reticulum associated with depletion of the glycogen particles were noted.
4) Large amount of lipid droplets were originated.
The results obtained in the present study suggested that malathion appeared to be cytotoxic to the liver cells of mice and that the organophosphorus compound would induce retrograde changes characterized by destruction of small organelles of the hepatocytes.
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