Changes in miR-122 Gene Expression in Liver Tissue and Serum Levels of ALT and AST Following Resistance Training and Boldenone Injection in Male Rats

Background and purpose: MicroRNA-122 (miR-122) is the most abundant liver–specific miRNA. It has been reported that miR-122 plays several biological roles such as iron homeostasis, tumor suppressor, hepatic fatty acid regulation, and in hepatocyte differentiation. The Purpose of this study was to investigate changes in liver miR-122 gene expression and serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes after resistance training and boldenone undecylenate (boldenone) steroid injection in male rats. Materials and methods: Twenty male Wistar rats were randomly divided into four groups: control (n=5), resistance training (n=5), resistance training+ boldenone injection (n=5), and boldenone injection (n=5). Resistance training was performed three sessions a week for eight weeks. Boldenone was injected twice per week (2mg/kg). Seventy-two hours after last training, blood and tissue samples were collected. Serum levels of ALT and AST were measured via photometric method and miR-122 gene expression in the liver was assessed by real-time PCR. Statistical analysis was conducted using SPSS V16. Results: Reduced expression of liver miR-122 was found in boldenone group, while the expression of miR-122 was higher in resistance training group, however, the difference was not significant (P= 0.514). Also, no significant difference was found in serum AST and ALT levels between the experimental groups (P= 1.00 and P= 0.527, respectively). Conclusion: In this study, liver miR-122 responded differently to resistance training and boldenone injection. However, clear understanding of its mechanism requires further studies.