Pulmonary effects of short term selenium deficiency

Area of Science:

• Biochemistry
• Toxicology
• Nutritional Science

Background:

• Selenium-dependent glutathione peroxidase (GPx) is crucial for reducing peroxides.
• Chronic selenium deficiency impairs GPx, potentially compensated by glutathione-S-transferase (GST).
• Short-term effects of acute selenium deficiency on lung antioxidant enzymes are not well-described.

Purpose of the Study:

• To investigate the time course of GPx depletion in rat lungs during acute selenium deficiency.
• To assess the activity of various antioxidant enzymes and the localization of GPx and SOD.
• To determine the impact of acute selenium deficiency on susceptibility to hyperoxia.

Main Methods:

• Rats were fed a selenium-deficient diet, with lung GPx measured every five days.
• After 20 days, lung enzyme activities (GPx, catalase, SOD, GR, G-6-PD, GST) were quantified.
• Immunohistochemistry was used for GPx and SOD localization, and hyperoxia tolerance was tested.

Main Results:

• Selenium deficiency significantly reduced lung GPx activity by one-third after 20 days.
• Cyanide-inhibited SOD activity decreased by approximately 50% in deficient rat lungs.
• Selenium-deficient rats exhibited increased susceptibility to lethal hyperoxia compared to controls.

Conclusions:

• This study demonstrates the earliest observed moderate loss of GPx activity due to acute selenium deficiency.
• Reduced GPx and potentially SOD activity contribute to increased susceptibility to pulmonary oxidant stress.
• Elemental deficiencies can intricately interact with antioxidant responses during severe oxidative stress.