Effect of vitamin C and/ or zinc overdose on circumvallate papillae of albino rats: an animal study

Background: Since COVID-19 was declared as a pandemic, a race began to find the natural micronutrients that can interfere with the virus cycle. The most recommended micronutrients were zinc and vitamin C. Aim of study: This work evaluated the impact of vitamin C and zinc, high doses alone, or combined on circumvallate papillae of albino rats. Methods: Twenty-four mature male albino rats were split equally into four groups. Group I (control group), group II got vitamin C, group III got zinc, and group IV got vitamin C and zinc. All treatments were given orally daily for 90 days. Upon completion of the experiment, serum malondialdehyde, superoxide dismutase, catalase and total antioxidant capacity were measured. Circumvallate papillae were inspected for the expression of nuclear factor kappa-β, histologically, ultrastructurally, and by comet assay. A statistical analysis was performed.Results: Statistical analysis revealed a significant decline in antioxidant markers but a significant rise in malondialdehyde blood levels in group IV, followed by groups ΙΙ, ΙΙΙ then Ι. Gene expression of nuclear factor kappa-β significantly increased in group IV, then came groups II, ΙΙΙ, and Ι. The histopathological and ultrastructural examination revealed group IV to have the most degenerative changes in circumvallate papillae followed by groups ΙΙ, ΙΙΙ and Ι. Comet assay showed different grades of DNA destruction descending from group IV, the highest grade of DNA destruction, followed by groups II, III and Ι. Conclusion: High doses of vitamin C, zinc and their combination resulted in degenerative changes in circumvallate papilla.