Arterial remodeling in chronic sinoaortic-denervated rats

Area of Science:

• Cardiovascular Physiology
• Vascular Biology
• Renal Physiology

Background:

• Blood pressure variability (BPV) refers to spontaneous blood pressure fluctuations.
• The chronic sinoaortic-denervated (SAD) rat model exhibits high BPV without sustained hypertension.
• Vascular remodeling in SAD rats remains poorly understood.

Purpose of the Study:

• To investigate blood pressure, vascular remodeling, and aortic angiotensin II levels in chronic SAD rats.
• To characterize structural and functional arterial changes following sinoaortic denervation.
• To explore the relationship between BPV, vascular remodeling, and the tissue renin-angiotensin system.

Main Methods:

• Continuous intra-arterial blood pressure recording in conscious rats.
• Histological analysis and computer imaging for arterial structural assessment.
• Isolated artery preparations for functional evaluation and radioimmunoassay for angiotensin II quantification.

Main Results:

• SAD rats showed significantly increased BPV over 24 hours, with no change in mean blood pressure.
• Vascular remodeling included increased arterial wall thickness, wall area, and wall-to-lumen ratio, indicative of vascular growth.
• Aortic contraction to norepinephrine was potentiated, and relaxation to acetylcholine was attenuated; aortic angiotensin II increased, while plasma levels remained unchanged.

Conclusions:

• Chronic sinoaortic denervation induces significant vascular remodeling in rats.
• This remodeling is associated with increased BPV and elevated aortic angiotensin II.
• The findings suggest an activated tissue renin-angiotensin system contributes to vascular changes and high BPV in SAD rats.