Objective To explore possible mechanism of Ningxintong Granule acting on vulnerable atherosclerotic plaques. Methods Sprague-Dawley（ SD） rats were given concentrated decoction of Ningxintong Granule 3

15

30

60 g /（ kg·d） by gavage for 4 days. Prepare serum medicated Ningxintong Granule isodose

5 times

10 times and 20 times. There were macrophages group

model group

serum medicated Ningxintong Granule isodose

5 times

10 times and 20 times groups. Besides macrophages group

foam cells models in other groups were established by normally grown human monocytic cell line（ THP-1） cells in vitro induction by oxidized low density lipoprotein. Serum medicated Ningxintong Granule groups were added medicated serum of corresponding dose and final concentrations were 3%. Test 4 times in each group. Detect the expression of scavenging receptor A（ SRA） and CD36 in each group. Results The expression of SRA and CD36 in model group was more than that in macrophages group（ P <0. 05）. The expression of SRA and CD36 in serum medicated Ningxintong Granule groups was less than that in model group（ P < 0. 01）. The expression of SRA and CD36 in serum medicated Ningxintong Granule 10 times group was less than that in other dose groups（ P < 0. 01）. Conclusion Ningxintong Granule could decrease the expression of SRA and CD36 and inhibit foam cells formation

which may be one of the molecular mechanisms of Ningxintong Granule acting on vulnerable atherosclerotic plaques.