Histological and histochemical alterations in the liver following intramuscular injection with a sublethal dose of the Egyptian cobra venom.

In the present study, the effects of intramuscular (i.m.) injection of a sublethal dose (0.015 microgram/gm b.wt.) of Naja haje venom were histologically and histochemically examined in the hepatic tissues of rabbits after 3, 6, and 12 hr. of envenomation. Three hours after venom injection, the hepatic cells showed a generalized cytoplasmic granulation and cellular swelling accompanied with narrowing of the sinusoidal spaces. Occurrence of inflammatory cells and hypertrophy of Kupffer cells were also noticed. After 6 hr. of envenomation, the hepatic tissues revealed severe cellular swelling, cytoplasmic deterioration, nuclear pyknosis, and appearance of numerous basophilic granules. The central veins were engorged with hemolyzed blood. Hepatic tissues investigated after 12 hr. of envenomation exhibited highly damaged hepatic cells to the extent that the individual cell cannot be identified and remnants of cell debris were seen intermixed together. Some hepatic cells were intensively swollen and their contents were dissoluted except for a few dusty cytoplasmic granules and pyknotic nuclei. The histochemical observations showed a time dependent depletion in polysaccharide, lipid, and protein contents in the hepatic cells of the envenomed groups. As for the nucleic acids, slight depletion of RNA together with no changes in DNA contents were observed by 3 hr. of envenomation. Nevertheless, severe degrees of RNA depletion and moderate contents of DNA were recorded in 6 hr. envenomed tissues. Highly obvious depletion of RNA and DNA were demonstrated by 12 hr. after venom injection. From the above results, it is obvious that cobra venom induces a hepatotoxic action reflected by alterations in the histological and histochemical patterns of the hepatic tissues. These alterations are initiated at early stages of envenomation and could indicate a disturbance in the functional activities of the liver during envenomation.