| Objective To investigate the effect and mechanism of stilbene glycoside (TSG) regulating microRNA-34a (miR-34a)/silent information regulator 1 (SIRT1) on osteoporosis (OP) rats. Methods Sixty female SD rats were randomly divided into sham operation group, model group, TSG group (80 mg/kg), miR-34a overexpression group (4 nmol/kg), TSG+miR-34a-agomir group (80 mg/kg+4 nmol/kg) and miR-34a overexpression negative control (antagomir-NC) group according to the random number table, with 10 rats in each group. Except for the sham operation group, the other groups were ovariectomized to establish osteoporosis model, after group administration, the levels of serum malondialdehyde (MDA) and glutathione catalase (GSH-Px) were detected; bone morphological changes, miR-34a and SIRT1 protein expression in peripheral blood were detected. The osteoblast precursor cell MC3T3-E1 cells were divided into control group, hydrogen peroxide (H2O2) treated group, TSG group, miR-34a-mimic group, miR-34a-NC group, TSG + miR-34a-mimic group, except the control group, the other groups were induced by H2O2 and were intervened with corresponding reagents. Hoechst 33258 staining was used to observe the apoptosis of osteoblasts; cellular miR-34a and SIRT1 protein, osteogenic differentiation protein alkaline phosphatase (ALP), osteopontin (OPN), and Osteocalcin (OCN) expression levels were detected. Results Compared with those in the model group, the trabecular fracture and reduction relieved in TSG group, the Tb.Sp in bone tissue, the expression of miR-34a and MDA in serum decreased (P<0.05), Conn.D, Tb.N and BMD in bone tissue, the level of serum GSH-Px and protein expression of SIRT1 increased (P<0.05). In miR-34a-agomir group, the trabecular fracture and reduction were further aggravated, the Tb.Sp in bone tissue, the expression of miR-34a and MDA in serum were further increased (P<0.05), Conn.D, Tb.N and BMD in bone tissue, the level of serum GSH-Px and protein expression of SIRT1 were further decreased (P<0.05). The changes of the above indexes in TSG+miR-34a-agomir group were contrary to those in TSG group, and the difference was statistically significant (P<0.05). After osteoblast precursor cells were treated with H2O2, compared with those in the control group, the apoptosis of osteoblasts in H2O2 treated group was serious, the expression of miR-34a was increased (P<0.05), and the protein expression of SIRT1, ALP, OPN and OCN was decreased (P<0.05). Compared with those in H2O2 treatment group, the apoptosis of osteoblasts in TSG group was decreased,the expression of miR-34a was decreased (P<0.05), and the protein expression of SIRT1, ALP, OPN and OCN was increased (P< 0.05);theapoptosis of osteoblasts of miR-34a-mimic was further aggravated, the expression of miR-34a-mimic were further increased (P<0.05),the protein expression of SIRT1, ALP, OPN and OCN were further decreased (P< 0.05).The above indexes of TSG+miR-34a-mimic group were opposite to those of TSG group (P<0.05).Conclusion TSG may inhibit the expression of miR-34a, up-regulate the expression of SIRT1 protein, inhibit the apoptosis of osteoblasts under oxidative stress, promote osteogenic differentiation, and improve the symptoms of osteopenia and abnormal bone tissue structure changes in OP rats. |