Relationship between osteoporosis and expression of Bcl-2 and CXCL12

The changes of expression of anti-apoptotic factor B-cell lymphoma 2 (Bcl-2) and chemokine C-X-C motif ligand 12 (CXCL12) in the pathological process of osteoporosis (OP) were investigated, to provide new ideas for the diagnosis and treatment of OP. A total of 60 postmenopausal women who needed to undergo hip replacement surgery were enrolled and divided into osteoporosis group (OP, n=32) and control group (CK, n=28) according to the results of dual-energy X-ray bone density measure; after operation, cancellousbone from the femoral head or femoral neck was removed, and osteoblasts and osteoclasts were isolated and cultured in vitro. The proliferation and apoptosis in the two groups of osteoblasts and osteoclasts were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetry and Annexin V/PI double staining method, respectively. The expression levels of Bcl-2 and CXCL12 mRNA and protein in the two groups of osteoblasts and osteoclasts were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The analysis of cell proliferation and apoptosis showed that compared with the CK group, osteoblast proliferation was significantly inhibited and apoptosis rate was distinctly increased in the OP group, compared with the CK group, osteoclast proliferation was distinctly enhanced and apoptosis rate was remarkably reduced in the OP group. The results of RT-qPCR and western blot analysis displayed that Bcl-2 and CXCL12 mRNA and protein levels in osteoblasts of the OP group were significantly lower than those of the CK group, while mRNA and protein levels of Bcl-2 and CXCL12 in osteoclast of the OP group were distinctly increased compared to those in the CK group. The incidence of OP is closely associated with the bone balance maintained by osteoblasts and osteoclasts, and this mechanism may be achieved by inhibiting osteoblast proliferation and osteoclast apoptosis via regulating Bcl-2 and CXCL12 gene expression changes.