Protective Effect of Increased Zinc Supply against Oxidative Damage of Sublingual Gland in Chronic Exposure to Cadmium: Experimental Study on Rats

Cadmium is one of the main chemical pollutants found in the daily environment of developed countries. Cigarettes are a significant source of that metal, which makes it important in terms of oral cavity health. The aim of this study was to determine if increased supply of zinc in chronic exposure to cadmium might protect the sublingual gland structure against oxidative damage. The experiment took 12 months and was conducted on 72 adult male rats. They were randomized into 9 groups. Eight groups received cadmium in drinking water (as CdCl(2)) at 5 or 50 mg Cd/dm(3) and/or zinc (as ZnCl(2)) at 30 or 60 mg Zn/dm(3). The control group received regular water. In the sublingual gland of all animal groups, levels of oxidative parameters were measured. The oxidative stress index was calculated as a TOS/TAS ratio. Cadmium exposure at 5 mg and 50 mg Cd/dm(3) induced oxidative stress in the sublingual glands of the rats. Cadmium reduced the TAS and GSH levels and increased LPO, H(2)O(2), TOS, and OSI. In cadmium exposure conditions, increasing the supply of zinc by 79% or 151%, as compared to the standard dietary intake of this microelement, completely prevented the reduction of TAS and GSH levels and accumulation of LPO, H(2)O(2), and TOS in the examined gland at both exposure levels to that metal. The outcome data confirm the protective effect of increased zinc intake on the sublingual gland tissue in chronic cadmium exposure.