Effect of modified compound calcium phosphate cement on the differentiation and osteogenesis of bone mesenchymal stem cells.

BACKGROUND: The aim of this study is to evaluate the effect of self-invented compound calcium phosphate cement upon the proliferation and osteogenesis of bone mesenchymal stem cells (BMSCs). METHODS: Four groups including traditional calcium phosphate cement, modified calcium phosphate cement, modified calcium phosphate cement plus bone morphogenetic protein (BMP), and control groups were established. The cell proliferation curve was delineated by MTT. The activity of BMSCs to synthesize alkaline phosphatase (AKP) was evaluated. The growth and invasion of BMSCs were observed. The expression levels of aggrecan, collagen I, collagen II, AKP, and OSX messenger RNA (mRNA) were measured by using RT-PCR. RESULTS: Compared with other groups, the BMSCs in the modified calcium phosphate cement group presented with loose microstructure and the BMSCs closely attached to the vector margin. At 7 days after co-culture, the expression of AKP in the modified calcium phosphate cement plus BMP group was significantly upregulated compared with those in other groups. In the modified calcium phosphate cement group, the BMSCs properly proliferated on the surface of bone cement and invaded into the cement space. At 10 days, the expression levels of aggrecan, collagen I, collagen II, AKP, and OSX mRNA in the modified calcium phosphate cement and modified calcium phosphate cement plus BMP groups were significantly upregulated than those in other groups. CONCLUSIONS: Modified compound calcium phosphate cement possesses excellent biocompatibility and osteogenic induction ability. Loose microstructure and large pore size create a favorable environment for BMSCs proliferation and vascular invasion, as an ideal vector for releasing BMP cytokines to mediate the differentiation and osteogenesis of BMSCs.

Characterization of vacuolar-ATPase and selective inhibition of vacuolar-H(+)-ATPase in osteoclasts.

V-ATPase plays important roles in controlling the extra- and intra-cellular pH in eukaryotic cell, which is most crucial for cellular processes. V-ATPases are composed of a peripheral V(1) domain responsible for ATP hydrolysis and integral V(0) domain responsible for proton translocation. Osteoclasts are multinucleated cells responsible for bone resorption and relate to many common lytic bone disorders such as osteoporosis, bone aseptic loosening, and tumor-induced bone loss. This review summarizes the structure and function of V-ATPase and its subunit, the role of V-ATPase subunits in osteoclast function, V-ATPase inhibitors for osteoclast function, and highlights the importance of V-ATPase as a potential prime target for anti-resorptive agents.

Expression of c-fos in gastric myenteric plexus and spinal cord of rats with cervical spondylosis.

AIM: To determine the expression of c-fos in gastric myenteric plexus and spinal cord of rats with cervical spondylosis and its clinical significance. METHODS: A cervical spondylosis model was established in rats by destroying the stability of cervical posterior column, and the cord segments C(4-6) and gastric antrum were collected 3, 4 and 5 mo after the operation. Rats with sham operation were used as controls. c-fos neuronal counter-staining was performed with an immunohistochemistry method. Every third sections from C(4-6) segments were drawn. The 10 most labeled c-fos-immunoreactive (Fos-IR) neurons were counted, and the average number was used for statistical analysis. The mean of Fos-IR neurons in myenteric plexus was calculated after counting Fos-IR neurons in 25 ganglia from each antral preparation, and expressed as a mean count per myenteric ganglion. RESULTS: There were a few c-fos-positive neurons in the cervical cord and antrum in the control group. There was an increased c-fos expression in model group 3, 4 and 5 mo after operation, whereas there was no significant increase in c-fos expression in the control group at 3, 4 and 5 mo. More importantly, there was a significant difference in c-fos expression between rats followed up for 3 mo and those for 5 mo in the model group (11.20+/-2.26 vs 27.68+/-4.36, P<0.05, for the cervical cord; and 11.3+/-2.3 vs 29.3+/-4.6, P<0.05, for the gastric antrum). There was no significant difference between rats followed up for 3 mo and those for 4 mo and between rats followed up for 4 mo and those for 5 mo in the model group. CONCLUSION: c-fos expression in gastric myenteric plexus was dramatically associated with that in the spinal cord in rats with cervical spondylosis, suggesting that the gastrointestinal function may be affected by cervical spondylosis. If this hypothesis is confirmed by further studies, functional gastrointestinal diseases such as functional dyspepsia and irritable bowel syndrome could be explained by neurogastroenterology.