脂多糖对大鼠不同组织中一氧化氮合成酶基因表达的影响

通过Northernblot和NADPH－心肌黄酶染色显示一氧化氮合成酶活性的组织化学分析方法，观察了脂多糖对大氧心脏、主动脉和肾组织中诱导型一氧化氮合成酶基因表达的影响及诱导型一氧化氮合成酶被脂多糖诱导表达的动力学。结果表明，未经脂多糖处理的大鼠诱导型一氧化氮合成酶基因在所检测的三种组织中表达活性很低，脂多糖作用于大鼠2h，心、肾和主动脉中的诱导型一氧化氮合成酶mRNA开始增加，6h达到峰值，此后，逐渐下降，24h回复到对照水平。一氧化氮合成酶组织化学染色显示，对照大鼠的组织细胞内存在较低的组成型一氧化氮合成酶活性，被脂多糖处理不同时间后，三种组织中的一氧化氮合成酶活性均显著升高，到24h仍维持在较高水平，提示诱导型一氧化氮合成酶被合成后，在组织细胞内较为稳定。

Effects of Lipopolysaccharide on the Expression of Nitric oxide Synthetase Gene in Different Rat Tissues

Aim To investigate the effect of lipopolysaccharide(LPS) on the expression of inducible nitric oxide syn-thetase (iNOS) gene and kinetics of the expression ofiNOS induction in rat heart, aorta and kidney tissues.Methods iNOS mRNA expression was determinedby Northern blot analysis and NOS activities were ob-served by NADPH-diaphorase staining.Results The expression activities of iNOS gene inrat three tissues were undetectable be fore LPS treat-ment. iNOS mRNA in the heart, aorta and kidney be-gan increased at 2 h after LPS treatment, and reacheda peak at 6 h, then decreased gradually and returned tocontrol levels at 24 h. NOS histochemical stainingshowed that there was some expression of constitutivenitric oxide synthetase (cNOS) in rat three tissues un-treated by LPS. NOS activities in the three tissues roseobviously after LPS treatment and still remained thehigher leve1 till 24 h. This result suggested that iNOSis considerably steady in the tissues after it is syn-thetized.Concluslon iNOS mRNA and activities are marked-ly induced by LPS in rat heart, aorta and kidney, andthe kinetics of induction is similar in the three tissues.