O2 free radical-mediated myocardial and vascular dysfunction.

Area of Science:

• Biochemistry
• Physiology
• Cardiovascular Research

Background:

• Electrolysis can generate reactive oxygen species (ROS).
• ROS are implicated in various physiological and pathological processes.
• Understanding ROS generation and effects in cardiovascular systems is crucial.

Purpose of the Study:

• To investigate the direct effects of electrolytically generated free radicals on isolated rabbit hearts.
• To determine the role of specific ROS in cardiac dysfunction and vascular permeability changes.
• To assess the protective potential of free radical scavengers.

Main Methods:

• Electrolysis of physiological buffer using a constant current.
• Perfusion of isolated rabbit hearts with the electrolyzed buffer.
• Measurement of coronary artery perfusion pressure (PP) and left ventricular end-diastolic pressure (LVEDP).
• Assessment of vascular permeability using 125I-labeled albumin.
• Administration of free radical scavengers: dimethyl sulfoxide (DMSO) and catalase (CAT).

Main Results:

• Electrolysis generated free radicals, confirmed by luminol assay.
• Isolated hearts showed increased PP (80 +/- 4 mmHg) and LVEDP (52 +/- 7 mmHg) after perfusion with electrolyzed buffer.
• Vascular permeability increased 8-fold, indicated by albumin retention.
• DMSO and CAT significantly protected hearts against functional and permeability changes.

Conclusions:

• Toxic oxygen species generated independently of blood elements can directly impact heart vasculature and function.
• Hydroxyl radicals (OH.) and hydrogen peroxide (H2O2) are likely involved in the observed cardiac and vascular effects.
• Free radical scavengers demonstrate therapeutic potential in mitigating ROS-induced cardiovascular damage.