Astragaloside IV Inhibits Proliferation and Promotes Apoptosis in Rat Vascular Smooth Muscle Cells under High Glucose Concentrationin vitro

Astragaloside IV is one of the main active ingredients of Radix astragali, which is a herbal remedy widely used in traditional Chinese medicine for the treatment of diabetes and cardiovascular diseases. However, its effects on vascular smooth muscle cell (VSMC), which plays a key role in the development of diabetic vascular complications, were not well studied. The present study was performed to examine the effects of astragaloside IV on proliferation, apoptosis and phenotypic modulation of VSMC under high D -glucose (25 mM). Application of astragaloside IV inhibited the proliferation and the rise of the proliferation index (PI) of VSMC induced by high glucose in a dose-dependent manner. Astragaloside IV induced apoptosis in VSMC under high glucose conditions, accompanied with typical morphological alterations and loss of mitochondrial membrane potential (Δ Ψ m ). In addition, Western blot analysis revealed that astragaloside IV increased the expression of α-smooth muscle actin, an important phenotypic modulation marker. In conclusion, astragaloside IV could inhibit high glucose-induced VSMC proliferation through intervention with the cell cycle, promoting apoptosis and regulating phenotypic modulation of VSMC, which strongly suggest that astragaloside IV could hinder the process of pathological vascular remodeling in diabetic patients. Abbreviations α-SMA:alpha-smooth muscle actin AS-IV:astragaloside IV DMEM:Dulbecco's modified Eagle's medium EDTA:ethylenediaminetetraacetic acid FCS:fetal calf serum FITC:fluorescein isothiocyanate HG:high glucose NG:normal glucose PBS:phosphate-buffered saline PI:proliferative index RSG:rosiglitazone SDS:sodium dodecyl sulfate SDS-PAGE:sodium dodecylsulfate polyacrylamide gel electrophoresis VSMC:vascular smooth muscle cells