氧化固醇对不同硒状态大鼠前列环素和内皮素的影响

目的 :　研究不同硒量下氧化固醇对血浆前列环素 (PGI2 )和内皮素 (ET)水平的影响。方法 :　采用低硒饲料饲养大鼠 1 3 w后 ,从尾静脉注射氧化固醇 (Ch- Ox) 3 β,5 α,6 β-三羟胆固醇 (3 - triol) ,2 4 h后采用放射免疫法测定其血浆 PGI2 、血栓烷 A2 (TXA2 )和 ET水平。结果 :　低硒组血硒含量及谷胱甘肽过氧化物酶 (GSH- Px)活性显著低于对照组 (P<0 .0 1 ) ,血浆 PGI2 水平也显著低于对照组 (P<0 .0 5 ) ,但其血浆脂质过氧化物 (LPO)水平及血浆 TXA2 水平显著高于对照组 (P<0 .0 5和 P<0 .0 1 ) ,从而导致 PGI2 /TXA2 比值显著低于对照组 (P<0 .0 1 )。对照 +3 -triol组血浆 PGI2 、TXA2 及 PGI2 /TXA2 与对照组相比均无显著性差异。虽然低硒 +3 - triol组血浆PGI2 与对照 +3 - triol组相比无显著性差异 ,但其血浆 TXA2 显著高于对照 +3 - triol组 (P<0 .0 0 1 )。低硒组与对照组相比 ,血浆 ET水平略有降低 ,差异不显著。对照组注射 3 - triol后血浆 ET水平显著升高 (P<0 .0 5 ) ,而低硒组注射 3 - triol后血浆 ET显著低于对照 +3 - triol组 (P<0 .0 5 )。给低硒 1 0 w的大鼠饮水补硒可一定程度上减小这些变化。结论 :　低硒和 Ch- Ox影响 PGI2 、TXA2 的浓度 ,使 PGI2 /TXA2 比值降低 ,Ch- Ox还使

EFFECTS OF CHOLESTEROL OXIDES ON PLASMA PROSTACYCLIN AND ENDOTHELIN LEVELS OF RATS IN DIFFERENT SELENIUM STATUS

Objective: Effects of cholesterol oxides (Ch-Ox) on plasma prostacyclin (PGI 2) and endothelin (ET) levels of rats in different selenium (Se) status were investigated. Methods: Weaning male Wistar rats were fed Se deficient diet (containing Se 0.038 mg/kg) and stock diet (Se 0.326 mg/kg, control group) respectively, for 13 weeks. One of Ch-Ox, cholestane-3 beta, 5 alpha, 6 beta-triol (3-triol) was injected into the rats through tail vein.24 h after treatment, the plasma PGI 2, thromboxane A 2 (TXA 2) and ET of animals were determined by radioimmunoassay. Results: Blood Se content, glutathione peroxidase activity and plasma PGI 2 levels of Se deficient rats were significantly lower than that of the control group (P<0.01, P<0.01 and P<0.05, respectively), but their plasma lipid peroxide levels and TXA 2 levels were significantly higher than that of the control group (P<0.05 and P<0.01, respectively). Thus their PGI 2/TXA 2 ratios were significantly lower than that of the control group (P<0.01). Plasma PGI 2 and TXA 2 levels and PGI 2/TXA 2 ratios did not change significantly in the control group injected 3-triol. Though plasma PGI 2 levels of Se deficient rats injected 3-triol had no significantly difference compared with the control group injected 3-triol, their plasma TXA 2 levels were significantly higher than that of the control group injected 3-triol (P<0.001). Furthermore, Se deficiency decreased ET concentration. Plasma ET levels of the control group injected 3-triol were significantly higher than the control group (P<0.05). Meanwhile, plasma ET of Se deficient rats injected 3-triol were significantly lower than the control group injected 3-triol (P<0.05). Supplementation of Se to Se deficient rats (fed Se deficient diet 10 weeks) could reverse the above effects. Conclusion: Se deficiency and Ch-Ox can affect plasma PGI 2 and TXA 2 concentration, and decrease plasma PGI 2/TXA 2 ratio. Ch-Ox can also increase plasma ET content. Supplementation of Se can reverse those effects. Thus we conclude that Se plays an important role in cytoprotection against cholesterol oxide-induced vascular damage in rats.