W. Pan et al., Genistein, daidzein and glycitein inhibit growth and DNA synthesis of aortic smooth muscle cells from stroke-prone spontaneously hypertensive rats, J NUTR, 131(4), 2001, pp. 1154-1158
Recent studies have reported that estrogen replacement therapy (ERT) reduce
s the risk of cardiovascular diseases in postmenopausal women. However, mec
hanisms responsible for this effect are not yet completely understood, and
ERT is associated with carcinogenic side effects in women and feminizing ef
fects in men. Because soybean isoflavones, a group of natural phytoestrogen
s, have only weak estrogenic activity and are not known to have side effect
s such as carcinogenesis and feminization, we evaluated the effects of geni
stein, daidzein and glycitein on the growth and DNA synthesis of aortic smo
oth muscle cells (SMC) from stroke-prone spontaneously hypertensive rats (S
HRSP). SMC were cultured in dishes and proliferated on 10% dextran-coated c
harcoal/fetal bovine serum, and then treated with 0.1-30 mu mol/L of genist
ein, daidzein or glycitein to investigate cell proliferation (cell number)
and DNA synthesis (cell proliferation ELISA system), respectively. We also
studied their effects on platelet-derived growth factor (PDGF)-BB (20 mug/L
)-induced SMC proliferation. Soybean isoflavones inhibited proliferation an
d DNA synthesis of SMC from SHRSP in a concentration-dependent manner. Inhi
bition was significant at 3 mu mol/L of genistein and 10 mu mol/L of both d
aidzein and glycitein. For significant inhibition of PDGF-BB-induced SMC pr
oliferation, concentrations as low as 0.1 mu mol/L of each isoflavone were
effective. These isoflavones, with their inhibitory effects on natural and
PDGF-BB-induced SMC proliferation, may be useful in attenuatating such prol
iferation, a basic mechanism involved in atherosclerotic vascular change, t
hereby preventing atherosclerotic cardiovascular diseases.