Suppression of low-density lipoprotein oxidation, vascular smooth muscle cell proliferation and migration by a herbal extract of Radix Astragali, Radix Codonopsis and Cortex Lycii

BACKGROUND: Atherosclerosis is a major cause of death in developed world. Atherosclerosis is characterized by low-density lipoprotein deposition in the arterial wall which ultimately begets the formation of lesions. Rupture of lesions finally leads to clinical events such as heart attack and stroke. Atherosclerosis is a complication associated with diabetes. In patients with diabetes, the risk of atherosclerosis is three to five folds greater than in non-diabetics. Our previous study showed that a herbal extract of Radix Astragali, Radix Codonopsis and Cortex Lycii, namely SR10, could improve glucose homeostasis both in vitro and in vivo. In this study, we want to further investigate the efficacy of SR10 in treating atherosclerosis. METHOD: The inhibitory effect of SR10 on low-density lipoprotein oxidation was investigated using free radical-induced erythrocyte hemolysis model and copper ion-induced low-density lipoprotein oxidation model. Since vascular smooth muscle cell proliferation and migration are important processes in atherogenesis, we also examined the effect of SR10 in inhibiting these events. RESULTS: Our results showed that SR10 inhibited erythrocyte hemolysis with IC(50 )value at 0.25 mg/ml and significantly prolonged low-density lipoprotein oxidation in vitro. SR10 attenuated platelet derived growth factor-BB-induced vascular smooth muscle cell proliferation by promoting cell cycle arrest at G(0)/G(1 )phase as well as inhibiting vascular smooth muscle cell migration. CONCLUSION: The potential application of SR10 in treating atherosclerosis has been implied in this study. Animal model will be needed to further verify the efficacy of SR10 in future.