Exercise preconditioning attenuates pressure overload-induced pathological cardiac hypertrophy.

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Molecular Cardiology

Background:

• Pathological cardiac hypertrophy involves myocyte remodeling and fibrosis, leading to cardiac dysfunction.
• Exercise preconditioning (EP) improves cardiac tolerance to ischemia-reperfusion injury but its role in pathological hypertrophy is less understood.

Purpose of the Study:

• To investigate the effects of exercise preconditioning (EP) on pathological cardiac hypertrophy induced by transverse aortic constriction (TAC) in rats.
• To explore the underlying molecular mechanisms, specifically the NF-κB signaling pathway.

Main Methods:

• Male Sprague-Dawley rats underwent 4 weeks of EP followed by 4-8 weeks of TAC to induce cardiac remodeling.
• Control groups received TAC without EP.
• Measurements included cardiac structure, function, fetal gene expression, and NF-κB pathway markers (IκBα, NF-κB p65, IL2).

Main Results:

• TAC induced significant cardiac hypertrophy, fibrosis, and systolic dysfunction, marked by increased ventricular wall thickness and fetal gene expression.
• EP treatment effectively inhibited these TAC-induced changes in the early stages (4 weeks post-TAC).
• EP suppressed IκBα degradation and NF-κB p65 nuclear translocation, reducing myocardial IL2 levels.

Conclusions:

• Exercise preconditioning can attenuate pathological cardiac hypertrophy induced by pressure overload.
• The protective effects of EP may be mediated through the inhibition of IκB degradation and blockade of the NF-κB signaling pathway.
• EP demonstrates potential therapeutic benefits in the early stages of pathological cardiac hypertrophy.