人血白蛋白及D-氨基半乳糖、脂多糖联合诱导建立大鼠慢加急性肝衰竭模型

目的建立与人慢加急性肝衰竭病理过程、生化改变相似,实用性、重复性好的动物模型,为研究慢加急性肝衰竭发生的病理生理机制、药物筛选及疗效评价提供适宜的模型。方法用人血清白蛋白免疫诱导建立肝纤维化大鼠模型,至肝纤维化达S4时予以D-氨基半乳糖与脂多糖联合攻击,计算动物病死率及生存时间,动态观察给药后4、8、12h肝功能、血浆细胞因子水平及病理变化,并以TUNEL法检测原位细胞凋亡,计算凋亡指数。结果人血白蛋白攻击6周时绝大多数大鼠形成经典肝硬化或重度肝纤维化。D-氨基半乳糖与脂多糖联合同时腹腔注射后90%大鼠死于肝衰竭,平均生存时间（16.1±3.7）h,病理表现为肝硬化再生结节内发生大块或亚大块坏死,纤维间隔保留。转氨酶及胆红素的变化符合肝细胞大片坏死时的功能改变,血清TNFα明显增高并与凋亡程度相一致。IL-10随给药时间延长而增高,与临床慢加急性肝衰竭患者变化相似。结论对人血白蛋白免疫诱导型肝硬化及肝纤维化大鼠给予D-氨基半乳糖/脂多糖联合急性攻击可建立慢加急性肝衰竭模型,本实验模拟了临床经常遇到的慢性肝病基础之上发生急性肝衰竭的部分病理生理过程。TNFα介导的肝细胞凋亡可能是该慢加急性肝衰竭重要病理机制之一。

Establishment of a D-galactosamine/lipopolysaccharide induced acute-on-chronic liver failure model in rats

OBJECTIVE: To establish a practical and reproducible animal model of human acute-on-chronic liver failure for further study of the pathophysiological mechanism of acute-on-chronic liver failure and for drug screening and evaluation in its treatment. METHODS: Immunological hepatic fibrosis was induced by human serum albumin in Wistar rats. In rats with early-stage cirrhosis (fibrosis stage IV), D-galactosamine and lipopolysaccharide were administered. Mortality and survival time were recorded in 20 rats. Ten rats were sacrificed at 4, 8, and 12 hours. Liver function tests and plasma cytokine levels were measured after D-galactosamine/lipopolysaccharide administration and liver pathology was studied. Cell apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. RESULTS: Most of the rats treated with human albumin developed cirrhosis and fibrosis, and 90% of them died from acute liver failure after administration of D-galactosamine/lipopolysaccharide, with a mean survival time of (16.1+/-3.7) hours. Liver histopathology showed massive or submassive necrosis of the regenerated nodules, while fibrosis septa were intact. Liver function tests were compatible with massive necrosis of hepatocytes. Plasma level of TNFalpha increased significantly, parallel with the degree of the hepatocytes apoptosis. Plasma IL-10 levels increased similarily as seen in patients with acute-on-chronic liver failure. CONCLUSION: We established an animal model of acute-on-chronic liver failure by treating rats with human serum albumin and later with D-galactosamine and lipopolysaccharide. TNFalpha-mediated liver cell apoptoses plays a very important role in the pathogenesis of acute liver failure.