Glucocorticoid induced apoptosis in osteoblast via a mitochondria-mediated pathway / 中国生化药物杂志

ABSTRACT

Objective To explore the molecular mechanism of osteoblast apoptosis mediated by glucocorticoid, provide experimental basis for clinical prevention and treatment of hormonal necrosis of femoral-head.Methods The MC3T3-E1 cells were divided into control group and three treatment group treated with different concentrations of dexamethasone (1, 10, 100μmol/L) for 24 hours.The apoptosis rate detected by TUNEL, the mitochondrial transmembrane electric potential after JC-1 staining by flow cytometry, the expression of Bax, Bcl-2 in mitochondrion and Cyt-C, apoptosis inducing factor ( AIF) in cytoplasm by Western blot.ResuIts With the increasing of Dex concentration, the rate of osteoblast apoptosis was significantly increased(F(3,28) =159.0,P=0.000), the positive cell rate of JC-1 stainning was significantly increased(F(3,28) =499.5,P=0.000), the expression of Bax(F(3,28) =17.4,P=0.000)in mitochondrion and Cyt-C(F(3,28) =22.4,P=0.000), AIF(F(3,28) =42.61,P=0.000)in cytoplasm were significantly increased.There were statistically significant difference of above indexes between control group and each experimental group(P<0.05).But there were no significant differences of Bcl-2 in mitochondrion among five groups(F(3,28) =0.62,P=0.607).ConcIusion Dexamethasone increases expression of Bax in mitochondrion, prompts mitochondrial permeability transition pore ( MPTP ) to be over-openning, induces apoptosis in osteoblast via a mitochondria-mediated pathway.