肝窦内皮细胞损伤在大鼠肝纤维化形成中的作用

目的 研究肝窦内皮细胞损伤在二甲基亚硝胺大鼠肝纤维化形成中的作用。方法 采用二甲基亚硝胺(dimethylnitrosamine,DMN)4周12次腹腔注射制备大鼠肝纤维化模型,应用电镜技术、免疫组织化学及图像分析方法结合血清生化测定,24周动态观察肝纤维化形成过程中肝窦内皮细胞损伤及其表型的改变。结果 造模2d后肝结构未见明显改变,肝窦内皮细胞(sinusoidal endothelial cell,SEC)远侧胞浆窗孔数减少、造模1周SEC失窗孔更明显,肝组织内未见明显变性坏死及纤维间隔形成,造模4周时见肝组织内大片出血坏死,有大量假小叶形成,内皮下出现SEC窗孔减少。SEC失窗孔早于肝细胞发生较为严重的坏死、肝纤维化的形成以及肝窦内皮下基底膜的形成。造模4周HA(ng/ml)和肝羟脯氨酸(ug/g)平均含量分别为231.30±143.80和223.04±37.09,对照组分别为56.50±18.10和61.55±20.85,t值在3.14～8.28,P<0.05。结论 DMN引起大鼠肝窦内皮细胞损伤及其表型改变可能是其诱导肝纤维化重要的始动机制之一。

Role of hepatic sinusoidal endothelium injury in hepatic fibrogenesis induced by dimethylnitrosamine in rats

Objective To study the role of hepatic sinusoidal endothelium injury during hepatic fibrogenesis induced by dimethylnitrosamine (DMN) in rats. Methods Hepatic fibrosis of rats was induced by administration of DMN intraperitoneally three times a week for 4 weeks. The animals were harvested on day 2 and week 1, 2, 3, 4, 5, 6, 8, 12, and 24. The formation of liver fibrosis and hepatic sinusoid capillarization were successively observed by morphological observation and other methods. Results Two days after treated with DMN, there was no obvious changes in the liver, but the fenestration of the sinusoidal endothelial cells decreased, and it became more obvious after one week. After four weeks, there was a large necrotic area and a number of pseudolobes appeared. The HA in the serum was lower than that of control (231.30 ng/ml+ 143.80 ng/ml vs 56.50 ng/ml+ 18.10 ng/ml; ?3.14, P<0.05), but the hydroxyproline content was obviously higher than that of control (223.04 ug/g+37.09 ug/g vs 61.55 ug/g+20.85 ng/g; t=8.28, P<0.05). Hepatic sinusoid capillarization was gradually formed and defenestration of the hepatic sinusoidal endothelium preceded the appearance of serious hepatocellular damage, hepatic fibrosis and basement membrane. Conclusions The damage and phenotypic alteration of the hepatic sinusoidal endothelium may be a vital issue triggering the liver fibrosis induced by DMN.