胆管结扎和四氯化碳诱导Wistar大鼠肝纤维化模型的建立及相关指标的对比分析

Comparison of hepatic fibrosis models and associated hepatic fibronectin expression in Wistar rats treated by bile duct ligation and CCl_4

目的比较胆管结扎(BDL)、四氯化碳(CCl4)诱导大鼠肝纤维化的生化指标、肝脏病理学及纤维连接蛋白(FN)的表达。方法 90只健康雄性Wistar大鼠,分为CCl4肝纤维化模型组(44只)及其对照组(6只)和BDL肝纤维化模型组(30只)及其对照组(10只)。CCl4肝纤维化模型组是采用50%的CCl4橄榄油溶液对大鼠进行腹腔注射的方法来制备模型,而BDL肝纤维化模型组则采用结扎大鼠胆总管的方法来制备。观察大鼠一般情况,生化方法测血清ALT、AST、TBil、DBil;ELISA法测血清透明质酸(HA)和层黏连蛋白(LN)水平。HE和Masson染色观察肝组织的病理学变化,免疫组织化学染色观察肝组织FN表达。计量资料组间比较采用t检验。结果血清生化学结果显示,BDL组大鼠自胆管结扎术后第7天开始,TBil及DBil即上升到较高水平且随后一直保持此水平,CCl4肝纤维化模型组大鼠2周始逐渐升高,至8周达高峰;BDL大鼠纤维化指标HA、LN水平显著高于同期CCl4模型组;CCl4模型组大鼠可见肝细胞弥漫性脂肪变性,汇管区-汇管区或汇管区-中央静脉间纤维间隔形成极为显著,BDL大鼠则表现为肝内胆管显著增生,炎性细胞浸润及纤维间隔形成同时存在;BDL组中FN的表达呈分散无规则型,且纤维组织细小,而CCl4组的FN多集中表达于小叶之间的间隔处,纤维组织粗大。结论 BDL和CCl4均可诱导大鼠肝纤维化,BDL较早引起肝功能及肝纤维化指标升高,可见明显胆管增生,CCl4则以脂肪变性为主;FN在两种模型中表达分布不同。

Objective To compare serum biochemical parameters, liver pathology, and fibronectin （FN） expression in Wister rats with he- patic fibrosis induced by bile duct ligation （BDL） and carbon tetrachloride （CCl_4 ）. Methods Ninety healthy male Wister rats were as- signed to CCl4 model （n =44）, CCl_4 control （n = 6 ）, BDL model （n = 30）, and BDL control groups （n = 10）. Animal models of hepatic fibrosis were established by intraperitoneal injection of olive oil solution containing 50% CCl_4 in the CCl_4 model group and by BDL in the BDL group. General conditions of rats were examined. Expression of serum alanine aminotransferase （ALT）, serum aspartate aminotrans- ferase （AST）, total bilirubin （TBil）, and direct bilirubin （DBil） was measured by biochemical analysis. Expression of serum hyaluronic acid （HA） and laminin （LN） was measured by ELISA assay. Pathological changes in liver tissue were examined through hematoxylin -eo- sin and Masson staining. Expression of FN was assayed by immunohistochemistry. Comparison between groups was made by t test. Results Serum biochemical analysis showed that TBil and DBil levels in BDL model rats increased to and maintained at relatively high levels from day 7 after surgery （P 〈 0.05 ） ; these two parameters in CCl_4 model rats increased gradually from week 2 and peaked at week 8 after injection （ P 〈 0.05 ）. The indicators of hepatic fibrosis, i. e. , HA and LN levels, were significantly higher in the BDL model group than in the CCl_4 model group. Pathologically, the CCl_4 model group showed diffuse fatty degeneration of liver cells, with extremely significant fiber interval for- mation in the portal area - portal area or the portal area - central vein; the BDL model group showed coexistence of significant intrahepatic bile duct hyperplasia, inflammatory cell infiltration, and fiber interval formation. In the BDL model group, FN expression was dispersive and irregular with thin fibrous tissues; in the CCl_4 model group, FN was mostly expressed in the interlobular septa, with thick fibrous tissues. Conclusion Both BDL and CCl_4 can induce hepatic fibrosis in rats. The former induces early increases in the indicators of liver function and hepatic fibrosis and results in significant bile duct hyperplasia, whereas the latter mainly causes fatty degeneration. FN expression shows different distribution patterns in the two hepatic fibrosis models induced by BDL and CCl_4.