体外循环中应用大剂量糖皮质激素的实验研究

Experimental Studies on the Theoretical Basis and the Receptor Mechanism of the Effects of High-dose Glucocorticoid during Cardiopulmonary Bypass

应用兔体外循环（ＣＰＢ）模型研究ＣＰＢ中应用大剂量糖皮质激素（ＧＣ）的理论依据及其作用的受体机制。结果显示，在ＣＰＢ期间血浆ＧＣ浓度显著升高、胸腺糖皮质激素受体（ＧＲ）水平显著降低，同时伴有血浆磷脂酶Ａ＿２（ＰＬＡ＿２）、脂质过氧化物（ＬＰＯ）水平显著升高；在ＣＰＢ中应用琥珀酸钠氢化考的松（２０ｍｇ／ｋｇ）能进一步提高血浆ＧＣ浓度、降低胸腺ＧＲ水平，却能显著抑制血浆ＰＬＡ＿２、ＬＰＯ的升高。表明ＣＰＢ能引起ＧＲ水平下降，从而引起ＧＣ效应的降低；ＣＰＢ中应用大剂量ＧＣ，能在ＧＲ减少的情况下维持和提高ＧＣ的效应。

The theoretical basis and the receptor mechanism of high-dose glucocorticoid (GC: Hydrocortisoni 20mg/kg) used during cardiopulmonary byaass (CPB) were explored on the rabbit CPB model. The results showed that the plasma concentration of GC increased markedly during CPB and was much higher in the CPB+GC group than in the control CPB group (P<0.0001). But the glucocorticoid receptors (GRs) of thymocytes decreased greatly after one hour of CPB and vere much lower in the CPB+GC group than in the CPB group (p<0.05). Meanwhile plasma phospholipase A2 activities and lipoperoxide contents increased significantly during CPB. but were much lower in the CPB+GC group than in the control CPB group (P<0.05～0.01).These results indicate that the GC biological response can be reduced by the decrease of GRs levels and maintained or enhanced by using high-dose GC during CPB.