Majallah-i Dānishgāh-i ̒Ulūm-i Pizishkī-i Bābul (Apr 2000)
Protective effects of Selenium on Lead impacts in functioning of submandibular salivary gland of rats
Abstract
Objective: Animal experiments have demonstrated that selenium can partly reduce nephrotoxicity and neurotoxicity of lead. There is no study about possible interactions between lead and selenium in functioning of salivary glands. This study was designed to explore the possible protective effects of selenium on lead-induced alterations on rat submandibular gland function. Methods: Pure submandibular saliva was collected intraorally by micro polyethylene cannula from anaesthetized rats using pilocarpine as secretagogue. Findings: A twenty-four day treatment with lead 0.04% and 0.05% as acetate in drinking water altered salivary function. Flow rate was significantly increased by lead (0.04% and 0.05%, P<0.01). The total protein and calcium concentrations of saliva were decreased significantly by either doses of lead (P<0.01). Also both doses of lead decreased the activity of NAG significantly (P<0.01). Selenium alone treatment (2.5 mg/L) in drinking water for 24 days did not induce any significant change in saliva secretory function but treatment with lead and selenium compensated the lead-induced decrease in NAG activity and concentrations of calcium and protein significantly at P<0.01 and raised them to levels close to those in controls. Increased flow rate by lead acetate was also affected by selenium co-treatment and reached that level in control. Conclusion: It is concluded that selenium can prevent lead-induced adverse effects on rat submandibular gland function. Properties of selenium as antioxidative, free radical scavenger and maintenance of cell membrane integrity are possible mechanisms of its protective effects. Further studies about interaction of lead and selenium in salivary glands at molecular level are proposed to explore the exact mechanism of their interaction.
