Cardiac effects of sodium selenite

Area of Science:

• Cardiology
• Toxicology
• Biochemistry

Background:

• The traditional view posits selenium toxicity to the heart at supra-dietary levels.
• Experimental evidence is needed to clarify the cardiac effects of selenium beyond deficiency correction.

Purpose of the Study:

• To investigate the effects of sodium selenite on cardiac function and tolerance to stressors.
• To determine if sodium selenite exerts a positive influence on stressed cardiac tissue.

Main Methods:

• Administered sodium selenite to mice and observed changes in LD50 (lethal dose, 50%) for ouabain and 2,4-dinitrophenol, and tolerance to nitrogen inhalation.
• Evaluated sodium selenite's effect on intact dog hearts and in isolated dog heart-lung preparations.
• Assessed the inotropic effects of sodium selenite on isolated ventricular segments under normal and oxygen-deficient conditions, with and without beta-adrenergic blockade.

Main Results:

• Sodium selenite increased the LD50 of ouabain and 2,4-dinitrophenol in mice, enhancing tolerance to nitrogen inhalation.
• In dog heart-lung preparations, sodium selenite reduced coronary vascular resistance.
• Sodium selenite induced a positive inotropic effect in isolated ventricular segments, even under oxygen deprivation and beta-adrenergic blockade.

Conclusions:

• The findings challenge the classical notion of selenium-induced cardiac toxicity.
• Sodium selenite demonstrates a direct positive influence on the heart, particularly when acutely stressed.
• These effects extend beyond the simple correction of selenium deficiency.