Dexamethasone induce osteoblast apoptosis in a duration- and dose-dependent manner.

OBJECTIVES

Osteoblasts play an important role in the process of osteogenesis and prevention of osteonecrosis. Dexamethasone, a type of glucocorticoids (GCs), induce apoptosis of osteoblasts and lead to the occurrence of non-traumatic osteonecrosis. This study aimed to explore the effects of different doses and duration of Dexamethasone on osteoblast apoptosis of rats in vitro.

METHODS

Proliferation and apoptosis of osteoblasts after Dexamethasone treatment were detected using cell counting kit-8 (CCK-8) assay and FITC-Annexin V/PI staining. The expressions of caspase-3 and -9 in osteoblasts after Dexamethasone treatment were analyzed using western blotting and qRT-PCR. Dexamethasone remarkably inhibited proliferation and induced apoptosis of osteoblasts in a dose-and duration-dependent manner.

RESULTS

As the intervention time extended, the expression of caspase-3 mRNA and caspase-9 mRNA in different Dexamethasone groups gradually increased in a duration-dependent manner. With the same time of intervention (12h, 24h, 48h), the expression of caspase-3 and -9 mRNA gradually increased in a dose-dependent manner. After treated with 5 * 10-8M, 5 * 10-7M, 5 * 10-6M and 5 * 10-5M Dexamethasone for 24 hours, the expression of cleaved caspase-3 and -9 protein increased in a dose-dependent manner.

CONCLUSION

Dexamethasone can induce osteoblast apoptosis in a duration- and dose-dependent manner.