Astaxanthin inhibits proliferation and induces apoptosis of LX-2 cells by regulating the miR-29b/Bcl-2 pathway

The aim of the present study was to investigate the role of microRNAs (miRNAs/miRs) in the anti-fibrotic effect of astaxanthin (AST), using the human hepatic stellate cell (HSC) line LX-2 as the research model. LX-2 cells were treated with various concentrations of AST (10, 20 and 40 µM) for 24 or 48 h. miR-29b was selected based on existing literature, and its targeting gene B cell lymphoma (Bcl)-2 was predicted by TargetScan and miRanda databases for further analysis. Interactions between miR-29b and Bcl-2 in the AST treated LX-2 cells were evaluated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. MTT analysis was used to analyze cell viability. Overexpression of miR-29b decreased the expression of Bcl-2 in AST-treated LX-2 cells, and silencing of it had the opposite effect. Additionally, Annexin V-fluorescein isothiocyanate/propidium iodide double staining and flow cytometry were used to evaluate the cell apoptosis, and overexpression of miR-29b increased cell apoptosis rates in AST-treated LX-2 cells; however, silencing of it had the opposite effect. RT-qPCR and western blotting demonstrated that AST induced LX-2 cells apoptosis which may be by regulating miR-29b, as indicated by inhibited Bcl-2 expression levels and elevated Bax and Caspase-3 expression levels. These results highlight an important role of miR-29b in the AST modulating LX-2 cells proliferation and apoptosis and implicate a potential mechanism of miR-29b and AST preventing liver fibrosis.