Cardiac anaphylaxis in the Sprague-Dawley rat

Area of Science:

• Cardiovascular Physiology
• Immunology
• Pharmacology

Background:

• Anaphylaxis is a severe systemic allergic reaction.
• The cardiovascular effects of anaphylaxis, particularly myocardial function, require further elucidation.
• Previous research indicates potential cardiac involvement during anaphylactic shock.

Purpose of the Study:

• To investigate the effects of anaphylaxis on cardiovascular parameters in a rat model.
• To assess myocardial function, including inotropism and lusitropism, following anaphylactic shock.
• To establish a reliable experimental model for studying anaphylaxis-induced cardiac dysfunction.

Main Methods:

• Induction of anaphylactic shock in Sprague-Dawley rats sensitized to ovalbumin.
• Measurement of mean aortic pressure, plasma histamine levels, and airway/esophageal pressures.
• Assessment of left ventricular diastolic pressure and contractility (dP/dt) in vivo.
• Evaluation of isolated perfused rat hearts challenged with antigen to determine left ventricular function (dP/dtmax).

Main Results:

• Anaphylaxis induced a rapid drop in mean aortic pressure and a significant increase in plasma histamine.
• Left ventricular diastolic pressure increased, while contractility (dP/dt) decreased significantly post-antigen challenge.
• Isolated hearts showed impaired left ventricular function, with reduced dP/dtmax, indicating compromised inotropism and lusitropism.
• No significant changes were observed in airway or esophageal pressures.

Conclusions:

• Anaphylaxis in rats leads to selective myocardial impairment.
• Reduced cardiac contractility and relaxation are key features of anaphylaxis-induced cardiac dysfunction.
• This rat model effectively demonstrates anaphylaxis-associated myocardial dysfunction, offering insights into its pathophysiology.