Oxygen toxicity in cultured aortic endothelium: selenium-induced partial protective effect

Area of Science:

• Biochemistry
• Cell Biology
• Toxicology

Background:

• Hyperoxia (95% O2) induces biochemical changes, cell damage, and loss.
• Endothelial cells are susceptible to oxidative stress.
• Selenium compounds, like selenomethionine, are known for their antioxidant properties.

Purpose of the Study:

• To investigate the protective effects of selenomethionine (Se-Met) against oxygen-induced toxicity in pig aortic endothelial cells.
• To determine the impact of Se-Met on antioxidant enzyme activity and cellular damage markers under hyperoxia.
• To explore the role of lipid peroxides in oxygen toxicity.

Main Methods:

• Culturing pig aortic endothelial cells in standard or Se-Met supplemented medium.
• Exposing cells to 95% O2 under normoxic and hyperoxic conditions.
• Measuring DNA and protein content, lactate dehydrogenase (LDH) release, and [3H]thymidine incorporation.
• Assessing glutathione peroxidase (G-Px) and other antioxidant enzyme activities.

Main Results:

• Se-Met supplementation significantly increased glutathione peroxidase (G-Px) activity.
• Se-Met conferred protection against O2-induced cell loss and damage, evidenced by preserved DNA/protein content and reduced LDH release.
• Se-Met did not prevent the O2-induced decrease in [3H]thymidine incorporation into DNA.
• Oxygen toxicity effects, excluding DNA synthesis inhibition, were partly prevented by Se-Met, suggesting a role for lipid peroxides.

Conclusions:

• Selenomethionine enhances antioxidant defense in endothelial cells by increasing G-Px activity.
• Se-Met provides partial protection against hyperoxia-induced cytotoxicity, likely by mitigating lipid peroxidation.
• The inhibitory effect of oxygen on DNA synthesis is independent of Se-Met-mediated protection.