[Buyang Huanwu Decoction delays vascular aging in rats through exosomal miR-590-5p signal-mediated macrophage polarization].

Abstract

Objectives: To investigate the mechanism underlying the inhibitory effect of Buyang Huanwu Decoction (BYHWD) on vascular aging.

Methods: Eighteen male SD rats were randomized into young group, intraperitoneal D-galactose injection-induced aging group, and BYHWD gavage group. The changes in pulse wave velocity (PWV), vascular SA-β-gal activity, and expressions of p16, p21 and SA‑β‑gal of the rats were examined. Serum exosomes were isolated from the rats, and after characterization using NTA and TEM and for surface markers and vascular cell markers, were examined for miR-590-5p expression using qRT-PCR. The M1/M2 macrophage ratio and cytokine levels were evaluated using immunofluorescence staining and qRT-PCR. Bioinformatics analysis and dual-luciferase reporter assays were carried out to predict the potential target genes of miR-590-5p and validate its targeting relationship with SLC8A3, whose expressions were detected in the vascular tissues of the rats by Western blotting.

Results: Compared with the young rats, the aging rats exhibited significantly increased PWV in the abdominal aorta with elevated vascular expressions of p16, p21 and SA-β-gal, which were all reversed by BYHWD treatment. The isolated serum exosomes were positive for CD63, CD81, CD31 and SM-22, and the exosomes from aging rats showed significantly downregulated expression of miR-590-5p, which was upregulated after BYHWD treatment. The aging rat vessels showed an increased M1/M2 macrophage ratio with elevated M1-specific cytokines and reduced M2-specific cytokines, and BYHWD treatment effectively inhibited M1 polarization of the macrophages. Pearson analysis revealed a negative correlation between exosomal miR-590-5p upregulation and the M1/M2 ratio. Bioinformatics analysis and dual-luciferase assays confirmed that miR-590-5p targets SLC8A3. Western blotting demonstrated increased SLC8A3 expression in aging rat vessels, which was downregulated after BYHWD treatment.

Conclusions: BYHWD attenuates vascular aging in rats by modulating macrophage M1 polarization and suppressing vascular inflammation via exosomal miR-590-5p-mediated downregulation of SLC8A3.