Anthocyanin attenuates high salt-induced hypertension via inhibiting the hyperactivity of the sympathetic nervous system

ABSTRACT

Background

Anthocyanin plays a protective role in cardiovascular disease through antioxidant effect. Whether anthocyanin can reduce salt-induced hypertension and the related mechanisms remain unclear.

Methods

Chronic infusion of vehicle (artificial cerebrospinal fluid, aCSF, 0.4 μL/h) or anthocyanin (10 mg/kg, 0.4 μL/h) into bilateral paraventricular nucleus (PVN) of Sprague-Dawley rats was performed. Then, the rats were fed a high salt diet (8% NaCl, HS) or normal salt diet (0.9%, NaCl, NS) for 4 weeks.

Results

High salt diet induced an increase in blood pressure and peripheral sympathetic nerve activity (increased LF/HF and decreased SDNN and RMSSD), which was accompanied by increased reactive oxygen species (ROS) production and angiotensin II type-1 receptor (AT₁R) expression and function in the PVN. Moreover, the NOD-like receptor protein 3 (NLRP3) and related inflammatory proteins (caspase-1) expression, the pro-inflammatory cytokine levels including IL-1β and TNF-α were higher in PVN of rats with a high salt diet. Bilateral PVN infusion of anthocyanin attenuated NLRP3-dependent inflammation (NLRP3, caspase-1, IL-1β and TNF-α) and ROS production, reduced AT₁R expression and function in PVN and lowered peripheral sympathetic nerve activity and blood pressure in rats with salt-induced hypertension.

Conclusions

Excessive salt intake activates NLRP3-dependent inflammation and oxidative stress and increased AT₁R expression and function in the PVN. Bilateral PVN infusion of anthocyanin lowers peripheral sympathetic nerve activity and blood pressure in rats with salt-induced hypertension by improvement of expression and function of AT₁R in the PVN through inhibiting NLRP3 related inflammatory and oxidative stress.

KEYWORDS:

• Anthocyanin
• salt-induced hypertension
• NLRP3
• sympathetic nerve activity
• paraventricular nucleus

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contribution

CX and JZ conceived and designed the experiments and wrote the manuscript; ZZ performed the experiments and analyzed the data; GG revised the manuscript; YZ and LG provided the project funding; CM approved the final version of the manuscript.

Additional information

Funding

The work was supported in part by grants from the National Key R&D Program of China (2018YFC1312703) and Natural Science Foundation of Chongqing (cstc2019jcyj-msxmX0576).