ABSTRACT
Forty five adult male albino rats were divided into two groups. Group I composed of 3 rats and were treated with a daily oral dose equivalent to 1/20 LD50 of thallium sulfate for 10 weeks to study the effect of chronic toxicity to this rodenticide on the submandibular salivary gland, gingiva and liver. Group II composed of 15 rats and served as controls. Chronic toxicity to thallium sulfated in major histochemical and ultrastructural changes in the organs and tissues under investigation where there was a marked reduction in the amount of glycogen and protein while there was an increase in RNA and glycos aminoglycans, however the later was decreased in hepatocytes of the treated fats. Ultrastructurally the submandibular salivary gland secretory cells, x surface epithelium and fibroblasts of the lamina propria of the gingira as well as the hepatocytes presented toxic deposition of electron dense granules of thallium with marked reduction in the nuclear chromatin, number of mitochodria, Golgi bodies as well as the secretory granules, increase in the rough endoplasmic reticulum of low electron density was found. Hepatocytes presented collection of fat globules, abnormal figures of electron dense material and vacuolization. Dilatation of the bile canalicului and narrowing of blood sinusoids were also detected