诱癌过程中鼠肝组织一氧化氮合酶的表达与改变

Expression and Alteration of Nitric Oxide Synthase in Liver Tissues during Development of Rat Hepatoma Induced by 2-FAA

目的：研究ＮＯ合酶在肝癌发生过程中的表达与改变。方法：以化学致癌剂２－ＦＡＡ喂饲ＳＤ大鼠，对鼠肝细胞在癌变过程中的组织学改变、一氧化氮合酶（ＮＯＳ）的表达和动态变化进行了研究。结果：当肝细胞轻度损伤时，肝组织中ＮＯＳ活性与对照组相比明显下降；当肝细胞表现为癌前病变和肝细胞完全癌变时，肝组织中ＮＯＳ的合成增加其比活性仍低于正常对照鼠；肝组织中ＮＯＳ与ＮＯ水平呈明显正相关（ｒ＝０５７，Ｐ＜００１），而与总ＲＮＡ浓度无相关性。结论：研究资料提示ＮＯＳ在诱癌早期的表达处于抑制状态以对肝细胞起保护作用；而肝癌形成阶段。

Aim:To explore the expression and changes of nitric oxide synthase (NOS) activity of liver tissues during development of rat hepatomas.Methods:The histological examination and the expression and dynamic alterations of NOS activities in the liver tissues were analysed in SD rats fed with 2-FAA Results :When the hepatocytes were damaged silghtly,NOS activities of liver tissues in experimental rats decreased obviosusly compared with control rats ;the synthesis of liver NOS increased but the mean specific activities of NOS were still lower in experimental groups than that in control group at stages of precancer and development of rat hepatoma.The positive correlation(r=0.57,P<0.01) was found between NOS activities and nitric oxide level but not between total RNA concentration and NOS level.Conclusion:The present data suggest that the expression of liver NOS is inhibited in protection from injury at early stage of experimental rats fed with 2-FAA and is accelerated for killing tumor cells at stage of hepatoma formation.