Transthoracic Ultrasound Improves Cardiac Function in Mice

Area of Science:

• Cardiology
• Biomedical Engineering
• Neuroscience

Background:

• Cardiac dysfunction increases mortality risk in various diseases.
• Vagus nerve stimulation is a researched cardioprotective strategy.
• Invasive vagus nerve stimulation carries risks of nerve damage.

Purpose of the Study:

• To investigate transthoracic ultrasound stimulation (US) as a noninvasive method for vagus nerve stimulation.
• To alleviate cardiac dysfunction induced by lipopolysaccharide (LPS) in mice.
• To evaluate the efficacy of US in improving cardiac function and reducing inflammation.

Main Methods:

• Development of a noninvasive transthoracic ultrasound system.
• Administration of LPS to induce cardiac dysfunction in anesthetized mice.
• Application of daily heart-targeting US or sham stimulation for 4 days.
• Assessment of cardiac function (ejection fraction, shortening fraction) and inflammatory cytokines (IL-6, IL-1β).
• Confirmation of vagus nerve involvement via cervical vagotomy.

Main Results:

• Daily US significantly improved left ventricular systolic function, ejection fraction, and shortening fraction.
• US treatment significantly reduced key inflammatory cytokines (IL-6, IL-1β).
• Cervical vagotomy abolished the cardioprotective effects of US, confirming vagus nerve mediation.
• Extended US treatment (14 days) improved cardiac function in aged mice.

Conclusions:

• Transthoracic ultrasound stimulation is a viable noninvasive approach for vagus nerve stimulation.
• This method effectively alleviates cardiac dysfunction and inflammation.
• US shows potential for treating cardiac dysfunction and rehabilitating peripheral organ function.