内毒素休克大鼠丝裂原活化蛋白激酶p38通路在生物喋呤诱生中的作用及其意义

目的　观察丝裂原活化蛋白激酶 (MAPK)p38信号通路抑制剂SB2 0 35 80对内毒素休克大鼠生物喋呤 (BH4 ) 一氧化氮 (NO)表达的影响及其意义。　方法　采用内毒素休克模型 ,5 6只大鼠随机分为正常对照组 (8只 )、内毒素休克组 (32只 )和SB2 0 35 80拮抗组 (1 6只 )。留取肝、肺、肾组织测定三磷酸鸟苷环水解酶I (GTP -CHI)与诱生型一氧化氮合酶 (iNOS)mRNA表达 ,同时检测血浆与组织中BH4 和NO水平的变化。　结果　内毒素攻击后 ,各组织GTP -CHI基因表达和BH4 水平明显升高 ,至伤后 2 4h仍持续于较高水平。组织iNOS基因表达和NO水平亦明显升高 ,其中肝、肺改变尤为显著。SB2 0 35 80处理后 ,肝、肺、肾组织GTP -CHImRNA表达分别于 1 2 ,2 4 ,2～ 1 2h受到显著抑制 (P <0 .0 5或 0 .0 1 ) ,肝组织BH4 水平 1 2h显著降低 (P <0 .0 5 ) ;同时 ,肝、肺和肾组织iNOSmRNA表达亦有不同程度下调 (P <0 .0 5或 0 .0 1 ) ,且肝、肺组织NO水平明显下降。　结论　p38MAPK信号途径参与了内毒素介导BH4 诱生的病理生理过程 ,抑制该通路能明显下调内毒素休克动物多器官BH4 NO系统的表达。

Role and significance of p38 mitogen-activated protein kinase signal transduction pathway in biopterin induction in rats with endotoxic shock

Objective To investigate the effect of the inhibitor SB203580 of p38 mitogen-activated protein kinase (MAPK) signal transduction pathway on biopterin (BH 4)/nitric oxide (NO) expression and elucidate the potential mechanism of MAPK in biopterin-mediated NO induction after endotoxic shock. Methods A total of 56 male Wistar rats were randomly divided into normal control group (n=8), endotoxic shock group (n=32) and SB203580 treatment group (n=16). After animals were sacrificed, tissue samples from the liver, the lungs as well as the kidneys were harvested to determine the expressions of guanosine triphosphate cyclohydrolase I (GTP-CHI) and inducible nitric oxide synthase (iNOS) mRNA and observe the changes of BH 4 and NO levels in blood and tissues. Results With endotoxin challenge, GTP-CHI mRNA expression and BH 4 levels were significantly elevated in various tissues and maintained at high levels up to 24 hours. Similarly, the iNOS mRNA expression and NO levels in the tissues significantly increased too, especially in the liver and the lungs. Treatment with SB203580 significantly down-regulated GTP-CHI mRNA expression in the liver, the lungs and the kidneys at 12, 24 and 2-12 hours, respectively (P<0.05 or P<0.01). In the meantime, BH 4 level in the liver reduced significantly at the 12th hour (P<0.05). In addition, iNOS mRNA expression in the liver, the lungs and the kidneys was significantly decreased at various degrees (P<0.05 or P<0.01). NO contents in the liver and the lungs were also markedly reduced. Conclusion p38 MAPK signal transduction may be involved in the pathological process of endotoxin-mediated BH 4 induction. Therefore, inhibition of p38 MAPK pathway can markedly down-regulate the expression of BH 4 /NO in rats with endotoxic shock.