Effects of nifedipine and Paeonia lactiflora on plasma TXB2 and 6-Keto-PGF1 alpha in cholesterol-fed rabbits

The authors examined the influences of nifedipine and Paeonia lactiflora (PL) on plasma LPO, TXB2 and 6-keto-PGF1 alpha in cholesterol-fed rabbits. In this study, oral administration of nifedipine (15 mg/kg per day) and PL (0.5 g/kg per day) with 2% cholesterol diet for 15 weeks caused 60.75% and 74.24% reduction in the lesion area of aorta respectively. The levels of plasma LPO, TXB2, cholesterol, phospholipid and calcium of the intimalmedia of the aorta in the treated groups were significantly lower than those in the control group, but the level of 6-keto-PGF1 alpha in the treated groups was significantly higher. The durations of TXB2 elevation and 6-keto-PGF1 alpha reduction were delayed. The ratio of TXB2/6-keto-PGF1 alpha tended to balance. The ratio of TXB2/6-keto-PGF1 alpha was significantly positive correlation with the percentage of lesion area of the aorta. It is demonstrated that calcium metabolism plays an important role in thromboxane, prostaglandin, and LPO synthesis. In conclusion, the inhibition of LPO production and the regulation of TXA2-PGI2 balance may be one of the mechanisms of anti-atherogenesis of calcium antagonists and PL.