Nitroprusside induces cardiomyocyte death: interaction with hydrogen peroxide

Area of Science:

• Cardiovascular Biology
• Cell Death Mechanisms
• Toxicology

Background:

• Sodium nitroprusside (SNP) is a vasodilator used clinically.
• The mechanisms underlying SNP-induced cardiomyocyte toxicity are not fully understood.
• Oxidative stress, particularly hydrogen peroxide (H2O2) generation, is a potential mediator.

Purpose of the Study:

• To investigate the hypothesis that SNP induces cardiomyocyte cell death via H2O2 generation.
• To characterize the type of cell death induced by SNP in cardiomyocytes.
• To elucidate the role of H2O2 in SNP-mediated cardiotoxicity.

Main Methods:

• Primary embryonic chick cardiomyocytes were cultured and treated with varying concentrations of SNP.
• Cell viability was assessed using trypan blue exclusion, MTT assay, and fluorescent activated cell sorting (FACS).
• Apoptosis and necrosis were identified by morphological changes, propidium iodide (PI) staining, and fluorescein diacetate staining. H2O2 production was measured, and the effects of catalase and deferoxamine were evaluated.

Main Results:

• SNP induced a significant, dose-dependent loss of cardiomyocyte viability, with apoptosis and necrosis observed.
• SNP treatment led to increased nitrite and H2O2 generation in the culture media.
• Catalase completely inhibited SNP-induced cell death at low concentrations and significantly reduced it at higher concentrations, implicating H2O2 in the mechanism.

Conclusions:

• SNP induces significant cell death in cardiomyocytes, characterized by both apoptosis and necrosis.
• Hydrogen peroxide (H2O2) generation is a critical mediator of SNP-induced cardiomyocyte toxicity.
• These findings highlight the vulnerability of cardiomyocytes to SNP and the role of oxidative stress in its pathogenesis.