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Abstract
SUMMARY
The present study was designed to describe the histopathological changes in both young and adult rats exposed to sodium fluoride via oral route. Moreover, the ultra-structural changes of the stomach and heart are described.
Rats were divided into 1) control group consisted of twenty albino rats. Control rats received food and water ad liptum. Rats were scarified at the end of the experiment and represented by ten adult and ten young albino rats 2) treated group consisted of seventy albino rats which divided into thirty five adult and thirty five young and received Na F in drinking water 18mg/kg dissolved in 250L water ad liptum. Four animals scarified every 15 days along the course of experiment. The rest of the surviving rats slaughtered at the end of experiment at 3 months. Adult rats were divided into four rats/cage; while young were six rats/cage.
Sodium fluoride induced osteoporotic changes, dental fluorosis, degeneration and necrosis of myocardial muscle, Abrasion and ulcers in gastric mucosa were also observed interstitial nephritis, vacuolar degeneration in cytoplasm of hepatocyte in liver and oedema with demyelination in the white matter of the cerbellum in brain were reported. Degeneration of bronchial epithelium, alveolar emphysema and interstitial pneumonia were also detected. Hemosidrosis in the spleen and testicular degeneration were described.
Transmation electron microscope in the heart muscle showed polymorphic mitochondria with condensed matrix and fragmentation of mitochondrial crests, vesiculation of rough endoplasmic reticulum and proliferation of smooth endoplasmic reticulum.
While scanning electron microscopy on mucosal surface of the stomach showed cracked clay appearance.
from these studies it was concluded that fluorine toxicity resulted in osteo- perotic changes in both young and adult rats .However the lesions in young rats was more severe than in adult rats. These means that bone in young rats was more susceptible to the deleterious effect of fluorine toxicity than those of adult. A similar conclusion could been proposed with respect to the teeth lesions as dental fluorosis characterized by hyperemia, hemorrhage of ameloplasts with vacuolation of dental enamel was only observed in young rats. However no lesions could be detected in adult rats.
Degenerative heart lesions were more serous in adult rats than in young ones a fact which could be utilized the higher susceptibility of the heart of adult rats than that of young one. It has been also proved that cardiac lesions could be the cause of death in both adult and young rats.
Gastric lesions were more deleterious in young rats than in adult rats; however with chronic exposure the lesions were prominent and serous consisting of erosions and ulcers with presence of clay cracked appearance.
Hepatic lesions were more serous in young than in adult rats. It consists of vacular degeneration with minimum inflammatory cells of mononuclear type.
Pulmonary lesions consist of interstitial pneumonia, emphysema, degeneration of the bronchial epithelium and vascular changes were more pronounced in adult than in young rats. This fact denotes deference in the pulmonary susceptibility for fluorine toxicity between adult and young rats.
Fluoride toxicity was capable of inducing nephrosis in adult rats. However in young rats it was associated with tubule-interstitial nephritis.
Oedema and demyelination of nerve fibers in cerebellar white matter .Also oedema with central chromatolysis in the granular cell layer were detected in the brain of young rats. However those of adult one showed only a mild degeneration of purkinje cell layer. This fact denotes that the neurotoxicity of fluorine is more serous in young rats than in adult rats.
Testicular lesions were more apparent in young rats than in adult rats lead to degeneration and disappearance of most of cells in germinal epithelium. However with chronic exposure testicular degeneration with the appearance of spermatide giant cells was the feature and in this will lead to infertility. This form of reproductive toxicity is of great economic importance and must be considered in animal kingdom especially in the area where environmental pollution with fluorine is suspected.