Abstract
Objective: To investigate the expression and role of autophagy in the progression of acute liver failure (ALF) using the mouse model of ALF induced by D-galactosamine/LPS (D-GalN/LPS). Methods: The C57BL/6 mice were used, and intraperitoneal injection of D-galactosamine (D-GalN) and lipopolysaccharide (LPS) was performed to establish the mouse model of ALF. The mice were divided into control group and 2-, 4-, and 6-hour D-GalN/LPS-induced ALF model groups. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured to assess liver function, and the pathological changes in liver tissue were observed to evaluate the status of liver injury. Quantitative real-time PCR was used to measure the expression of autophagy-related genes, Western blot was used to measure the expression of autophagy-related proteins in liver tissue, and a fluorescence microscope was used to observe the expression of autophagosome in the progression of liver failure. A one-way ANOVA was used for comparison of means of multiple samples between any two groups (LSD-t test for data with homogeneity of variance and Games-Howell method for data with heterogeneity of variance).P< 0.05 was considered statistically significant. Results: The ALF model groups showed gradual liver impairment over the time of D-GalN/LPS stimulation. There were significant increases in ALT and AST after 4 hours; the pathological injury of liver tissue gradually aggravated over the time of D-GalN/LPS stimulation and fulfilled the criteria for ALF at 6 hours. The mRNA and protein expression of autophagy-related genes (ATG-7, ATG-5, Beclin-1, Lamp-1, and LC3a) increased in the early and medium stages of ALF (2 and 4 hours) and decreased after ALF progressed to liver failure (6 hours). As was observed via the fluorescence microscope, the 4-hour D-GalN/LPS-induced ALF model group showed the highest expression of autophagosome. Conclusion: The expression of autophagy gradually increases in the early and medium stages of ALF and decreases when ALF progresses to liver failure. Therefore, autophagy plays an important role in the pathogenesis of ALF.