Modulatory Role of Zinc Chloride on Cadmium Chloride-induced Histological Changes in Tongue Papillae of Rats

Background: Cadmium (Cd) is recognized as one of the most toxic heavy metals with very strong accumulation. In dentistry, Cd may be released from dentures, intraoral alloys. Some strategies have been postulated to neutralize heavy metal intoxication such as zinc supplementation. The aim of this research project was to investigate the effect of Cd on tongue papillae of rats, and the possible modulatory role of zinc.

Materials and Methods: In vivo study was carried out on forty adult male Albino rats. All the animals were maintained on standard laboratory diet, rats were divided into four equal groups: GI: Rats were drinking purified water for 6 months. GII: Zinc was given in aque­ous solutions of zinc chloride for the same period as group I. GIII: Rats were receiving Cd also in the form of aqueous solutions of cadmium chloride for the same period as the other groups. GIV: Rats were receiving similar cadmium treatment as group III along with zinc treatment as group II. After 6 months, rats were sacrificed and tongue was studied under light microscope using routine H&E stain.

Results: Results of this study demonstrated that 70%, 70%, 50%, 30%, 70%, and 70% of the total cases of group III revealed abnormal shape of filiform papillae, hyperkeratosis, acanthosis, epithelial dysplasia and inflammatory cell infiltration with dilation of blood vessels respectively, while all cases (100%) in group I and II showed normal histological features. These Differences were statistically significant (p<0.005). Cases in group IV showed abnormal shape of filiform papillae (70%) without any changes at the cell level in the epithelium and the connective tissue.

Conclusion: Cadmium chloride may cause histopathological changes on the tongue mucosa of rats. While zinc chloride may prevent histopathological cell changes.