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Photoacoustic imaging of in vivo hemodynamic responses to sodium nitroprusside
Dong Zhang1,2, Ran Li3,4, Maomao Chen2
1Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.
Abstract:
The in vivo hemodynamic impact of sodium nitroprusside (SNP), a widely used antihypertensive agent, has not been well studied. Here, we applied functional optical-resolution photoacoustic microscopy (OR-PAM) to study the hemodynamic responses to SNP in mice in vivo. As expected, after the application of SNP, the systemic blood pressure (BP) was reduced by 53%. The OR-PAM results show that SNP induced an arterial vasodilation of 24% and 23% in the brain and skin, respectively. A weaker venous vasodilation of 9% and 5% was also observed in the brain and skin, respectively. The results show two different types of blood oxygenation response. In mice with decreased blood oxygenation, the arterial and venous oxygenation was respectively reduced by 6% and 13% in the brain, as well as by 7% and 18% in the skin. In mice with increased blood oxygenation, arterial and venous oxygenation was raised by 4% and 22% in the brain, as well as by 1% and 9% in the skin. We observed venous change clearly lagged the arterial change in the skin, but not in the brain. Our results collectively show a correlation among SNP induced changes in systemic BP, vessel size and blood oxygenation.
Insights
Sodium nitroprusside (SNP) lowers blood pressure and causes vasodilation in arteries and veins. This study reveals correlations between SNP
Area of Science:
- Physiology
- Biomedical Engineering
- Pharmacology
Background:
- The in vivo hemodynamic effects of sodium nitroprusside (SNP), a common antihypertensive, remain incompletely understood.
- Investigating SNP's impact on blood vessels and oxygenation is crucial for clinical applications.
Purpose of the Study:
- To investigate the in vivo hemodynamic responses to sodium nitroprusside (SNP) using functional optical-resolution photoacoustic microscopy (OR-PAM).
- To analyze SNP-induced changes in systemic blood pressure, arterial and venous vasodilation, and blood oxygenation in both brain and skin tissues in mice.
Main Methods:
- Functional optical-resolution photoacoustic microscopy (OR-PAM) was employed to monitor hemodynamic changes in vivo.
- Mice were administered SNP, and subsequent alterations in blood pressure, vessel diameter, and blood oxygenation were quantified in the brain and skin.
Main Results:
- SNP administration resulted in a 53% reduction in systemic blood pressure.
- Arterial vasodilation of 24% (brain) and 23% (skin) and venous vasodilation of 9% (brain) and 5% (skin) were observed.
- Two distinct blood oxygenation responses were noted, with SNP causing either decreases or increases in arterial and venous oxygenation, and a lag in venous oxygenation changes was observed in the skin but not the brain.
Conclusions:
- SNP induces significant arterial and venous vasodilation and alters blood oxygenation in a complex manner.
- The findings highlight a correlation between SNP-induced changes in systemic blood pressure, vessel size, and blood oxygenation.
- OR-PAM provides valuable insights into the in vivo hemodynamic effects of antihypertensive agents like SNP.
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