To investigate the effect of brain and muscle arant-like-1 (Bmal1) and miRNA-155-5p on the proliferation ability and aging of bone marrow mesenchymal stem cells (BMMSCs) to provide an experimental basis for elucidating the mechanism of bone senescence.

BMMSCs were extracted from the femur medullary cavity of 1-month-old mice, purified and cultured via the whole bone marrow mesenchymal adherent method and passed to P3. The characteristics of BMMSCs were detected by flow cytometry. BMMSCs were transfected with lentivirus to construct stable miR-155-5p and Bmal1 overexpression/interference BMMSCs. shRNA-transfected BMMSCs were identified by qRT-PCR. The proliferation activities of miR-155-5p and Bmal1 overexpression/interference BMMSCs were detected via CCK-8 assay. The apoptosis rates were measured by flow cytometry. The aging status of BMMSCs was identified with the senescence-associated β-galactosidase (SA-β-Gal) test. The expression of senescence-related genes P16 and P53 was detected by qRT-PCR.

The shRNA-transfected BMMSCs were successfully generated. The proliferation ability decreased, and the apoptosis rates, the activity of SA-β-Gal and the relative expression levels of P53 and P16 increased when miRNA-155-5p was overexpressed. The proliferation ability increased, and the apoptosis rates, the activity of SA-β-Gal and the relative expression levels of P53 and P16 decreased when miRNA-155-5p was inhibited. The effect of Bmal1 is opposite to that of miRNA-155-5p.

The expression of Bmal1 promotes the proliferation and antiaging ability of BMMSCs, while miRNA-155-5p inhibits the proliferation and accelerates the aging of BMMSCs.