Serum comparative proteomic analysis of radiation-induced hepatic injury in cirrhotic rats

AIM: To investigate the differential expression of serum proteins in cirrhotic SD rats for exploring the pathogenesis and identifying the potential biomarkers of radiation-induced hepatic injury. METHODS: Liver cirrhosis was induced in 8 healthy SD rats with subcutaneous injection of carbon tetrachloride (CCl₄) for 6 weeks and then the animals were randomly divided into 2 groups (4 rats in each group): control group (CCl₄ alone) and experimental group (CCl₄ plus radiation). The latter received hemi-liver radiation with single dose of 15 Gy while the former did not receive radiation. Total serum proteins of the 2 groups were extracted 6 h after radiation. Two-dimensional gel electrophoresis (2-DE) were performed to look for differentially expressed proteins. These proteins were then analyzed and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Western bloltting was used to validate the expression of heparanase and hepatocyte growth factor receptor in all independent series of serum samples. RESULTS: Two-dimensional gel images were acquired with good resolution and repetition. Thirty-three differentially expressed proteins were selected and 12 proteins were successfully identified by MS, in which 5 were up-regulated while 7 were down-regulated. The increased level of heparanase and decreased level of hepatocyte growth factor receptor were further confirmed by Western blotting. CONCLUSION: Twelve proteins associated with radiation-induced hepatic injury are successfully characterized by serum comparative proteomics. Heparanase and hepatocyte growth factor receptor might be useful for detecting and monitoring radiation-induced hepatic injury.