Paeonol attenuated vascular fibrosis through regulating Treg/Th17 balance in gut microbiota-dependent manner / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE Atherosclerosis (AS) is a chronic inflammatory disease characterized by the accumulation of lipids, vascular fibrosis, and inflammation. Paeonol (Pae) is a natural phenolic compounds isolated from a traditional Chinese medicine, Cortex Moutan, which exhibits anti-AS effects. Our previous work demonstrated that gut microbiota plays an important role during AS treatment as it affects the efficacy of Pae. However, the mechanism of Pae in protect?ing against vascular fibrosis as related to gut microbiota has yet to be elucidated. To investigate the anti-fibrosis effect of Pae on AS mice and demonstrate the underlying gut microbiota-dependent mechanism. METHODS ApoE-/- mice were fed with high-fat-diet (HFD) to replicate the AS model. HE and Masson staining were used to observe the plaque forma?tion and collagen deposition. Gut microbiota alteration and short-chain fatty acids (SCFAs) production were analyzed through 16S rRNA sequencing and LC-MS/MS. The frequency of immune cells in spleen were phenotyped by flow cytometry. The mRNA expression of aortic inflammatory cytokines were detected by qRT-PCR. The protein expression of LOX and fibrosis related indicators were examined by Western blotting. RESULTS Pae restricted the development of AS and collagen deposition. Notably, the anti-fibrosis effect of Pae was achieved by regulating the gut microbiota. 16S rRNA sequencing and LC-MS/MS data indicated that the relative abundance of SCFAs-producing bacteria and SCFAs production was increased. Additionally, Pae administration selectively up-regulated the frequency of regulatory T (Treg) cells as well as down-regulated the ratio of T helper type 17 (Th17) cells in the spleen of AS mice, improving the Treg/Th17 balance. In addition, as expected, Pae intervention significantly down-regulate the mRNA expression levels of pro-inflammatory cytokines IL-1β, IL-6, TNF-αand IL-17 in the aorta tissue, up-regulate the levels of anti-inflammatory factor IL-10, a marker of Treg cells. Finally, Pae's intervention in the gut microbiota resulted in the restoration of the balance of Treg/Th17, which indirectly down-regulated the protein expression level of LOX and fibrosis-related indicators (MMP-2/9 and collagenⅠ/Ⅲ). CONCLUSION Pae attenuates vascular fibrosis in a gut microbiota-dependent manner. The under?lying protective mechanism is associated with the improved Treg/Th17 balance in spleen mediated through the increased microbiota-derived SCFAs production.