一氧化氮在肝硬变大鼠低蛋白血症中的作用

The role of nitric oxide in hypoproteinemia in cirrhotic rats

目的探讨一氧化氮（ＮＯ）在肝硬变低蛋白血症中的作用。方法利用硫代乙酰胺（ＴＡＡ）腹腔注射大鼠诱导肝功能的变化，并用辅酶Ⅱ（ＮＡＤＰＨ）硫辛酰胺脱氢酶组织化学法显示不同肝功能时期肝脏一氧化氮合成酶（ＮＯＳ）的分布。结果正常鼠肝脏ＮＯＳ染色阴性；大鼠肝功能异常但无低蛋白血症时，肝小叶周边有少量散在的ＮＯＳ阳性细胞，至肝硬变有明显低蛋白血症时，假小叶内肝细胞均为ＮＯＳ染色阳性；停止注射ＴＡＡ４周后，大鼠肝功能逐渐恢复，但仍有低蛋白血症，此时假小叶内肝细胞仍为ＮＯＳ阳性，仅染色稍浅于肝功能明显异常时。结论肝硬变时肝细胞内ＮＯＳ被激活而产生ＮＯ，后者通过抑制肝细胞合成蛋白质而可能参与肝硬变时低蛋白血症的形成。

Objective To explore the role of nitric oxide in hypoproteinemia in cirrhotic rats. Methods The dynamic distribution of nitric oxide synthase (NOS) in the liver in different hepatic function period, which induced by thioacetamide (TAA) in rats, was observed by using NADPH diaphorase histochemistry. Results The staining of NOS in the hepatocytes of the normal rats was negative. A few of NOS positive cells were seen in the margin of hepatic lobulus when hepatic dysfunction was presented, but no hypoproteinemia occurred. When the hepatic function was severely damaged and liver cirrhosis was formed, the staining of NOS in the hepatocytes in the pseudolobule was strong positive. However when there was only hypoproteinemia in the cirrhotic rats, the NOS positive reaction of hepatocytes in the pseudolobulus still existed. Conclusions These findings suggested that the hypoproteinemia in the cirrhosis rat might be partly due to the synthesis of NO in the hepatocytes, because NO may suppress the synthesis of protein.