Astragali Radix-Angelicae Sinensis Radix inhibits the activation of vascular adventitial fibroblasts and vascular intimal proliferation by regulating the TGF-β1/Smad2/3 pathway

Ethnopharmacological relevance: Astragali Radix-Angelicae Sinensis Radix is an important traditional Chinese medicine used for the treatment of cardiovascular diseases. Our previous studies have shown that Astragali Radix-Angelicae Sinensis Radix can inhibit vascular intimal hyperplasia and improve the blood vessel wall's ECM deposition, among which six main active components can be absorbed into the blood, suggesting that these components may be the main pharmacodynamic substances of Astragali Radix-Angelicae Sinensis Radix against vascular intimal hyperplasia.

Aim of the study: A mouse model of atherosclerosis was used to study the relationship between the anti-intimal hyperplasia effect of Astragali Radix-Angelicae Sinensis Radix and the inhibition of VAF activation and ECM synthesis. Furthermore, an in vitro rat VAF activation model was used. The effects of the main active ingredients of Astragali Radix-Angelicae Sinensis Radix on the proliferation, migration and ECM synthesis of VAF were observed. The mechanism of its action was investigated by focusing on TGF-β1/Smads signaling pathway.

Materials and methods: Male ApoE^-/- mice were used to establish an AS model. Observe the morphological changes of blood vessels, the expression of Vimentin, α-SMA, ECM-related factors and TGF-β1/Smads signaling pathway-related proteins. Ang Ⅱ was used to induce the VAF activation model. The cell activity, cell proliferation, cell migration, cell phenotypic markers, ECM-related factors, cell cycle regulation-related proteins and TGF-β1/Smads signaling pathway-related proteins were determined. On this basis, TGF-β1/Smads signaling pathway agonists and inhibitors were used to study the effects of the compatibility of six active components on TGF-β1/Smads signaling pathway.

Results: Astragali Radix-Angelicae Sinensis Radix can reduce aortic intimal hyperplasia, inhibit the expression of aortic α-SMA, Vimentin, ECM components, TGF-β1, p-Samd2 and p-Samd3. Cell experiments showed that the six active ingredients could inhibit the proliferation and migration of VAF to varying degrees, inhibit the expression of α-SMA, cell cycle promoters, ECM components, up-regulate the expression of Vimentin, P21, MMP2 and MMP9. The above effects were enhanced after the combination of the six components. The 6 components and their combinations could inhibit the expression of TGF-β1/Smads signaling pathway-related proteins and up-regulate the expression of Samd7 to varying degrees. The above effects were enhanced after the combination of the 6 components. TGF-β1/Smads signaling pathway inhibitor LY2157299 showed similar effects with the six components. The inhibitory effects of the six active ingredients on TGF-β1/Smads signaling pathway-related proteins and the promotion of Smad7 expression were attenuated when agonists were added into the six active ingredient combinations. However, adding TGFβ1/Smads signaling pathway inhibitor EGF to the six active ingredient combinations had no effect on the above effects.

Conclusion: Astragali Radix-Angelicae Sinensis Radix can inhibit intimal hyperplasia, VAF activation, and ECM synthesis in atherosclerosis. The six active ingredients may be the main pharmacological substances of Astragali Radix-Angelicae Sinensis Radix to inhibit the activation of VAF, and the combination of six ingredients can enhance their effects, which may be mediated by inhibiting the activation of the TGF-β1/Smad2/3 signaling pathway.