【作者】 巫国谊；

【导师】 赵有蓉；

【作者基本信息】 重庆医科大学 ， 内科学， 2004， 硕士

【摘要】 目的：选用SD大鼠建立急性肝损伤动物模型，观察N-乙酰半胱氨酸(N-Acetylcysteine，NAC)对肝损伤大鼠肝脏的保护作用。并通过检测血液和肝组织中还原型谷胱甘肽(Glutathione，GSH)和一氧化氮(Nitric oxide，NO)浓度以及不同型别一氧化氮合酶(Nitric oxide synthase，NOS)活性，探讨NAC对肝损伤模型保护作用的药理机制。 方法： 1、NAC在D-氨基半乳糖(D-galactopyranoside，D-gal)致肝损伤动物模型中的作用 选用SD大鼠建立D-gal致急性肝损伤模型。分别给予除正常对照组以外的各组大鼠以D-gal 1g／kg腹腔注射一次，建立肝损伤动物模型。模型建立分别于D-gal造模后6h、12h、18h给予两治疗组不同剂量的NAC腹腔注射，共三次。各组动物均于造模后24h采集血及肝脏组织标本。分别观察比较各组大鼠血清中ALT、AST、TBIL水平及PT的变化，同时比较各组大鼠肝脏病理变化的异同。屯庆医利人学硕卜学位论文 2、NAc对D一gal致肝损伤模型药理作川机制研究 2.1 .NAC对D一gal致肝损伤大鼠血清及肝组织GSH浓度的影响 本试验采用高效液相色谱分析(High Performance LiquidChromatograPhy，HPLC)方法测定GSH水平，比较各组大鼠血清及肝组织中GSH水平。 2.2.NAC对D一gal致肝损伤大鼠血清及肝组织NO浓度及不同型别NOS活性的影响 采用南京建成生物工程研究所生产的NO测试盒(硝酸还原酶法)分别测定各组大鼠血清及肝组织中NO浓度，以3H精氨酸转化实验测定NOS活性方法分别测定各组大鼠肝脏组织中cNOS和iNOS活性。 结果: 1、不同剂量的两NAC组大鼠血清ALT、AST、TBIL水平明显降低，PT缩短，大鼠肝脏形态结构及炎性浸润有所改善，大剂量NAC组改善肝功能指标更显著。 2、NAC组可以显著的提高肝损伤大鼠血清及肝组织中耗竭的GSH含量，加大NAC剂量可进一步提高体内GSH水平。 3、与模型组相比，两组NAC大鼠血清NO水平均明显升高，而肝组织中NO水平降低，其水平改变均以大剂量NAC组更为显著。较之模型组，NAC可以提高的cNOS活性而降低iNOS李舌性。 结论:屯庆医科人学硕行货了方沦文 1、NAC对实验性大鼠肝损伤有明显的保护作用，可改善大鼠的肝功能和病理学形态。 2、NAC对实验性大鼠肝损伤保护作川机制之一可能是通过补充血清及肝脏组织中的耗竭的GSH水平;同时也可以通过提高血清中NO水平而增加组织灌流，降低肝脏组织中有毒性作用的NO水平而产生保护作用;NAC可以激活cNOS活性而抑制iNOS活性，这一结果进一步提示NAC对机体内NO水平影响可能是通过改变不同型别NOS活性而产生的。更多还原

【Abstract】 Aim: To select the SD rat to establish D-gal(D-galactopyranoside) induced hepatic injury model. To study the protective effect of NAC (N-Acetylcysteine) against the hepatic injury. The mechanisms of the protect activities were investigated by compare the GSH and NO (nitric oxide) level in serum and liver tissue of each rat group. Additional, to investigate the activities of two types of NOS(nitric oxide synthase) in rat’s liver to elucidate the changes of NO level with NAC treatment.Method:1. The hepatoprotective effect of NAC in D-gal induced hepatic injury model of SD ratThe acute liver injury model were induced by D-gal. All the rats in NAC treat group were intraperitoneal injected with NAC at 6 hours after that D-gal were given. Each NAC treat group was given NAC 0.1mmol/kg or 0.19mmol/kg three times every 6 hours. Collecting the serum, plasma and liver tissue of these rats at 24 hours after the D-gal was given. The ALT(alanine aminotransferase), AS T(aspartate aminotransferase), TBiL (total bilirubin) level and PT(Prothrombin time) were assayed. And, the pathologic changes of each group were observed. 2. To study the mechanisms of the hepatoprotective activities of NAC2.1. To detect the GSH level in serum and liver tissue of each groupThe GSH concentration were mensurated by HPLC (High Performance Liquid Chromatography). Comparing the GSH level in serum and liver tissues of each group.2.2. To detect the NO level of in serum and liver tissue after NAC or GSH were given. And to detect two type of NOS activities in liver tissue:The NO concentration were determined by the Nitric Oxide quantitation Kit from Nanjing Jiancheng Bioengineering Institute. The activities of iNOS and cNOS in the liver tissue were detected by monitoring the conversion of 3H-Arginine.Result:1. The ALT, AST and TBil level in serum were markedly decreased and it showed a shortened prothrombin time in the two NAC treated groups.7The morphological findings of hepatic tissue from acute liver injured rats were significantly improved with NAC treatment.2. The GSH level in serum and liver tissue was significantly increased in the NAC treatment group. It showed a significant increase of the GSH concentration in liver tissue of which treated with higher dose group of NAC than that lower dose group.3. The hepatic NO concentration of acute liver injured rat group was significant decreased in the NAC treatment group. Whereas the serum NO concentration was significant increased in the same group. That conclusion may also be proved by detect the two types of NOS activities in liver tissue. It shown that the iNOS were inhibited but the cNOS were activated with NAC treatment.Conclusion:1. Treat with NAC intraperitoneal injection can protect hepatocyte from morphological and functional destruction of the hepatic injured rats induced by D-gal.2. The effect of liver injured rats treatment with NAC may probably interpret by the mechanisms as follows: (1). The GSH level in liver tissue and serum of D-gal induced hepatic injured rats was significant increase with NAC treatment. (2). The NO concentration in serum is also increase with NAC treatment, and that makes the liver perfusion increased. But the NO concentration in liver tissue is decreased in NAC treated group. It cutdown the liver injury induced by high concentration of NO in liver tissue. This conclusion was also been demonstrated by detect the iNOS and cNOS activities in liver tissue.更多还原