Kaempferol inhibits apoptosis in vascular smooth muscle induced by a component of oxidized LDL.

Antioxidants such as flavonoids afford protection against oxysterols-induced toxicity. We have investigated the effect of kaempferol and rutin, active components of red wine, in the apoptosis induced by 7beta-hydroxycholesterol in rat vascular smooth muscle cells. 7beta-Hydroxycholesterol induced apoptosis in vascular smooth muscle which include BcL-x(L) degradation, caspase-3 activation and DNA fragmentation. The apoptosis induced by 7beta-hydroxycholesterol was prevented by pretreatment with kaempferol (10-30 microM), but not with rutin. Interestingly preincubation with the estrogen receptor alpha antagonist ICI 182,780 (1 microM) prior to kaempferol partially reverted the antiapoptotic effect of this flavonoid on caspase-3 activation and DNA fragmentation induced by 7beta-hydroxycholesterol. In conclusion, the flavonoid kaempferol, unlike rutin, diminished the apoptosis induced by a component of oxidized low-density lipproteins (oxLDL). This effect was partially mediated by the estrogen receptor alpha.