In this study,we examined the protective effects of Danshen both on endothelial progenitor cells(EPCs) in patients with hypercholesterolemia and on in-vitro EPCs of healthy volunteers.In the clinical study,we randomly divided 24 subjects with hypercholesterolemia into two groups(the control group and the Danshen-treated group).At the end of two weeks of treatment,the EPC cellular functions of both groups were tested.The results indicated that,compared to the control group,EPCs in the Danshen-treated group showed significantly better cellular functions,which was manifested in the cloning number,the proliferation capacity,the number of EPC adhesions,and cell migration.In the subsequent in-vitro experiments,EPCs were treated with vehicle,oxidized low-density lipoprotein(Ox-LDL,100 μg/ml),or Ox-LDL(100 μg/ml) plus different concentrations of Danshen(Danshensu 2,10,or 50 μg/ml,respectively) for 24 h.The results showed that Danshen treatments can prevent the detrimental effects of Ox-LDL on EPC cellular functions measured by proliferation capacity(0.24±0.08,0.37±0.11,0.30±0.04 vs.0.13±0.02,P<0.05,P<0.01,and P<0.01,respectively),and adhesion ability(63.00±11.60,70.00±10.80,85.50±11.41 vs.40.50±6.85,all P<0.01).Compared to the group treated with Ox-LDL alone,Danshen treatment significantly decreased the lipid peroxidation end product malondialdehyde(MDA) [(4.34±0.54),(3.98±0.47),(3.46±0.31) vs.(5.57±0.64) nmol/ml,all P<0.01],increased the production of superoxide dismutase(SOD) [(29.74±0.71),(31.09±0.83),(30.41±0.65) vs.(14.76±3.99) U/ml,all P<0.01],and lowered the expression of interleukin-6(IL-6) [(24.62±7.69),(27.04±3.14),(33.38±18.86) vs.(230.67±33.53) pg/ml,all P<0.01] and tumor necrosis factor-α(TNF-α) [(41.72±6.10),(17.02±6.82),(3.73±2.26) vs.(228.71±41.53) pg/ml,all P<0.01] in Ox-LDL treated EPCs.These results suggest that Danshen may exert a protective effect through its antioxidant and anti-inflammatory features.