[Osteoprotegerin and receptor activator of nuclear factor kappa B ligand mRNAs expression in BMSCs of glucocorticoid-induced necrosis of the femoral head patients].

OBJECTIVE: To investigate the expression levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) mRNAs in BMSCs in patients suffering glucocorticoid-induced necrosis of the femoral head (GNFH), and to discuss the relationship between OPG/RANKL system and GNFH.

METHODS: The bone tissue and BMSCs of femoral head were collected from 35 patients suffering GNFH (experimental group) and from 21 patients suffering fracture of femoral neck (control group). The ratio of men to women was 4:3 in two groups, aged 41 to 70 years (mean 55.34 years in the experimental group and mean 55.33 years in the control group). The patients of experimental group received over 3 weeks' glucocorticoid treatment or more than 1 week's high-dose glucocorticoid therapy in recent 2 years, but patients of the control group did not receive more than 1 week's hormone therapy. In 2 groups, the microstructure of bone tissue of femoral head was detected by HE staining. The BMSCs were isolated and cultured by adherent-wall method; the expression levels of OPG and RANKL mRNAs were examined by real-time quantitative polymerase chain reaction and the ratio of OPG mRNA to RANKL mRNA was calculated.

RESULTS: Bone trabeculae and bone units were replaced by interrupted bone fragments, which were surrounded by inflammation and granulation tissue and few osteocytes were seen in bone lacunae in the experimental group. In control group, bone trabeculae and bone units were made by complete lamellar bone which surrounded blood vessels and osteocytes were seen in lacunae. The expression levels of OPG mRNA in the experimental group (0.37 +/- 0.12) was significantly lower than that in the control group (0.47 +/- 0.13), and the levels of RANKL mRNA in the experimental group (1.12 +/- 0.39) was significantly higher than that in the control group (0.84 +/- 0.24), showing statistically significant difference (P < 0.05). The ratio of OPG mRNA to RANKL mRNA in the experimental group (0.37 +/- 0.17) was significantly lower than that in the control group (0.61 +/- 0.26, P < 0.05).

CONCLUSION: The GNFH may be related to the expression levels of OPG mRNA and RANKL mRNA in BMSCs.