Effect of Panax notoginseng saponins on increased proliferation of cultured aortic smooth muscle cells stimulated by hypercholesterolemic serum

Panax notoginseng saponins (PNS) was extracted from a Chinese herb medicine. After preparation of cultured aortic smooth muscle cell (SMC) from primary aortic explants, the cytotoxicity of hypercholesterolemic serum (HCS) for cultured cells was determined by trypan blue exclusion test, and [3H]thymidine incorporation and cell numbers were counted at the same time. The results showed that HCS (0.5 mg cholesterol.ml-1) increased the incorporation of [3H]thymidine into cultured cells (3722 +/- 440 vs 1655 +/- 288 dpm/microgram cell proteins, P < 0.01), stimulated the proliferation of SMC [(6.5 +/- 1.5) x 10(5) vs (4.3 +/- 1.2) x10(5) cells/plate, P < 0.01], and that high concentration HCS (final cholesterol concentration 2 mg.ml-1) was cytotoxic to the cultured cells. PNS (100 and 400 micrograms.ml-1) decreased the incorporation of [3H]thymidine into SMC in culture with or without HCS (1292 +/- 260 and 982 +/- 314 or 4111 +/- 886 and 2361 +/- 751 dpm/microgram cell protein), and inhibited the proliferation of the cultured cells [(3.3 +/- 0.7) x 10(5) and (2.9 +/- 0.7) x 10(5) or (4.7 +/- 1.4) x 10(5) and (4.1 +/- 1.2) x 10(5) cells/plate). We conclude that PNS can inhibit the proliferation of aortic SMC stimulated by HCS. These results also suggest that HCS may play an atherogenic role in the arterial wall and that PNS may prevent atherosclerosis and inhibit progression of the atherosclerotic lesions by interfering with the proliferation of arterial SMC.