OBJECTIVETo investigate the changes in expression of the ACE2/Ang(1-7)/Mas receptor axis' components that occur during progression of liver fibrosis using a rat model system.

METHODSThirty-six adult male Wistar rats, were randomly assigned to groups of normal control (n = 6; no manipulation) and liver fibrosis (n = 30; given a subcutaneous injection of 40% chronic carbon tetrachloride (CCl4)). At post-injection days 15, 30, 45, 60 and 75, 1 control rat and 6 modeled rats were sacrificed for analysis. Histopathological analysis of liver tissue was performed with hematoxylin-eosin and rapid Masson staining. Protein expression level of Ang(1-7) was determined by enzyme-linked immunosorbent assay, and of ACE2 and Mas receptor was evaluated by immunohistochemistry. Real-time PCR was used to measure the mRNA expression levels of ACE2 and Mas receptor.

RESULTSThe expression levels of ACE2, Ang(1-7) and Mas receptor showed a statistically significant upward trend that followed the progression of fibrosis up to post-injection day 60 (P less than 0.01), but the significant increase was not seen from day 60 to day 75.

CONCLUSIONEach component of the ACE2/Ang(1-7)/Mas receptor axis shows differential expression during the development of liver fibrosis and may contribute to disease progression.