Related Experiment Video
Updated: Jun 16, 2026
Monitoring Blood-Brain Barrier Opening in Rats with a Preclinical Focused Ultrasound System
Published on: September 13, 2024
[Impact of ultrasound-mediated microbubbles on myocardial vascular permeability in rats]
Bing-jie Zhou1, Dao-gang Zha, Rong-sheng DU
1Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. bingjie.2007@yahoo.com.cn
Objective:
To investigate the impact of high-dose microbubbles induced by high mechanical index myocardial contrast echocardiography (MCE) on vascular permeability and its recovery time in rats.
Methods:
Thirty male Wistar rats were randomized into 4 MCE groups (groups A-D) and a control group. In the MCE groups, Evans blue was injected at 10 s before MCE (A), immediately after the end of MCE (B), and at 5 min (C) and 20 min after the end of MCE (D). In the control group, the microbubbles and Evans blue were injected at the end of a 5-min ultrasound exposure. All the rats were sacrificed 5 min after Evans blue injection, and the content of Evans blue in the myocardium and the percentage of Evans blue leakage area were determined.
Results:
The percentage of Evans blue leakage area in groups A, B and C were significantly higher than that in the control group (P<0.05), while the percentage was similar between group D and the control group (P>0.05). Evans blue contents in groups A and B were significantly higher than that in the control group (P<0.05), but groups C and D showed comparable contents with the control group E (P>0.05). No significant changes of the heart rates and premature beat number were observed during and after MCE in these groups (P>0.05).
Conclusion:
High mechanical index MCE and a high contrast dose may induce increased microvascular leakage in rats, and the vascular permeability can recover in 20 min after MCE.
Insights
High mechanical index myocardial contrast echocardiography (MCE) with high contrast doses increases vascular permeability in rats. Permeability recovers within 20 minutes post-MCE, with no observed cardiac side effects.
Area of Science:
- Cardiovascular Research
- Medical Imaging
- Physiology
Context:
- Myocardial contrast echocardiography (MCE) utilizes microbubbles for enhanced cardiac imaging.
- High mechanical index (MI) settings may influence microvascular integrity.
- Understanding the impact of MCE parameters on vascular permeability is crucial for safe clinical application.
Purpose:
- To investigate the effects of high mechanical index MCE with high microbubble doses on rat myocardial vascular permeability.
- To determine the time course of vascular permeability recovery following MCE.
Summary:
- Thirty male Wistar rats underwent MCE with varying Evans blue injection timings relative to the procedure.
- Increased vascular permeability and Evans blue leakage were observed when injection occurred before or immediately after MCE.
- Vascular permeability returned to baseline levels by 20 minutes post-MCE, with no significant changes in heart rate or arrhythmias.
Impact:
- High MI MCE and high contrast doses can transiently increase microvascular leakage.
- Vascular permeability recovers within 20 minutes, suggesting a safe window for MCE procedures.
- Findings inform the safe use of MCE in preclinical and potentially clinical settings.
