Effect of intracellular free calcium on simvastatin induced vascular smooth muscle cells apoptosis in rats
Jin Huang · Zhongguo yaolixue yu dulixue zazhi · 2003
AIM To investigate the mechanisms involved in simvastatin induced apoptosis in vascular smooth muscle cells(VSMC). METHODS Cultured VSMC was treated with simvastatin. Intracellular free calcium concentration ([Ca 2+ ] i) was measured by fluorescent Ca 2+ sensitive probe fura 2 acetoxylmethyl ester(Fura 2/AM), apop totic changes were distinguished by annexin Ⅴ binding , DNA fragment and caspase 3 activation. RESULTS When incubated with 30 μmol·L -1 simvastatin, [Ca 2+ ] i in VSMC increased with time and reached to (336±52) nmol·L -1 at 6 h, more than 3 fold of control (P0.01 , n=5). Verapamil (80 μmol·L -1 ), a membrane voltage dependent Ca 2+ channel blocker, inhibited the increase of free calcium concentration induced by simvastatin from (336±52) nmol·L -1 to (144±34)nmol·L -1 (P0.01) . Caspase 3 also activated by simvastatin after 12 h. Verapamil could efficiently inhibit simvastatin induced caspase 3 activation. Furthermore, 80 μmol·L -1 verapamil could decreased simvastatin induced apoptosis rate from (24.2±1.7)% to (7.9±0.6)% (P 0.01) and also prevented simvastatin induced DNA laddering. CONCLUSION Simvastatin could increase [Ca 2+ ] i mainly through calcium influx from extracellular solution and then induces apoptosis.