Objective: To determine the differential protein and mRNA expressions of mitochondria fusion protein-2 (Mfn2) in hepatic tissues in conditions of cirrhosis and acute on chronic liver failure using rat model systems,and to determine the correlative effects on production of adenosine triphosphate (ATP) and reactive oxygen species (ROS).
Methods: A liver cirrhotic rat model (LC rats) was established by intraperitoneal injection of carbon tetrachloride (CCl4,in vegetable oil),and these mice were subsequently used (10 weeks later) to establish the acute on chronic liver failure rat model (LF rats) by injecting lipopolysaccharide and D-amino-galactose.Control groups (normal controls,NC rats) were established for each model by intraperitoneal injection of vegetable oil only.Protein expression of Mfn2 in liver was quantified by western blotting with fluorescence densitometry and immunofluorescence staining,and mRNA expression was measured by real-time fluorescence quantitative PCR.ROS levels in liver were measured by fluorescence spectrophotometry,and ATP content was measured by bioluminescence assay.Significance of inter-group differences was assessed by one-way ANOVA,and correlations were determined using bivariate statistical modeling.
Results: Mfn2 protein expression was significantly lower in the liver tissues from modeled rats than that from the control rats (LC:0.051+/-0.004 and LF:0.037+/-0.007 vs.NC:0.254+/-0.008;F=444.98,P less than 0.05).The mRNA expression followed the same trend of lower expression (LC:21.21+/-0.93 and LF:24.35+/-0.85 vs.NC:19.09+/-0.69; F=66.941,P less than 0.05).The ATP content in liver tissues was also significantly lower in the modeled rats (LC:2.07+/-0.05 mol/L and LF:1.81+/-0.11 mol/L vs.NC:3.24+/-0.08 mol/L; F =574.21,P less than 0.05).Lower Mfn2 expression was correlated with lower ATP content (r =0.982) and higher ROS content (r =0.803).
Conclusion: Reduced Mfn2 expression in liver tissue may cause a decrease in ATP synthesis and increase in ROS generation,thereby disrupting metabolism and increasing oxidative stress in the liver under conditions of cirrhosis and liver failure.