| Objective To investigate the effect of miR-135b targeting glycogen synthase kinase 3B (GSK3B) on dexamethasone-induced apoptosis of osteoblasts. Methods CCK8 was used to detect the effect of dexamethasone on the viability of MC3T3-E1 cells. The optimal concentration was selected for subsequent experiments. Flow cytometry was used to detect apoptosis. RT-PCR was used to detect the expression of miR-135b and GSK3B. The effect of luciferase reporting experiments verified the relationship between miR-135b and GSK3B targeting. The cells were divided into control group, dexamethasone group (Dex), negative control mimics group (mimics NC), miR-135b group, and miR-135b+pc-GSK3B group. The protein expression was detected with Western blotting. Results Compared to those in the Control group, apoptosis increased, the expression of miR-135b decreased, and the expression of GSK3B increased in the Dex group. The luciferase report experiment showed that there was a targeting relationship between miR-135b and GSK3B. Compared to those in the Dex group, the apoptosis of miR-135b group reduced, the levels of GSK3B, Bax, cleaved caspase-3 and cleaved caspase-9 protein decreased, and Bcl-2 protein level increased. Compared to those in the miR-135b group, the apoptosis of the miR-135b + pc-GSK3B group increased, the levels of GSK3B, Bax, cleaved caspase-3 and cleaved caspase-9 increased, and the level of Bcl-2 decreased. Conclusion miR-135b inhibits dexamethasone-induced apoptosis of osteoblasts by targeting GSK3B. This effect is related to the regulation of Bax/Bcl-2 expression and caspase-3/9 activation. |