ABSTRACT
Objective:To investigate the effects of myeloid-derived growth factor(MYDGF) on inflammatory response and osteoclast differentiation of RAW264.7 cells.Methods:The RAW264.7 osteoclast precursor cells were cultured and treated with different concentrations of recombinant MYDGF protein(rMYDGF), and their cell viability was assessed using the MTT assay. RAW264.7 cells were induced with lipopolysaccharide(LPS) to induce inflammation, and the expression of inflammatory mediators and cell polarization were observed after intervention with rMYDGF. The RAW264.7 cells were induced for osteoclast differentiation using receptor activator of nuclear factor-κB ligand(RANKL), and rMYDGF was added for intervention. Osteoclast differentiation was evaluated by tartrate-resistant acid phosphatase(TRAP) staining. The osteoclast resorption pits and the number of actin rings(F-actin rings) were observed under a microscope. Reverse transcription PCR was performed to detect the expression of activated T cell nuclear factor 1(Nfatc1), cathepsin K(CTSK), and c-Fos genes during osteoclast differentiation. The protein phosphorylation levels of nuclear factor-κB(NF-κB) signaling pathway proteins were detected using Western blotting.Results:MTT assay showed that rMYDGF did not significantly inhibit the viability of RAW264.7 cell when the concentration was lower than 100 ng/mL. Moreover, rMYDGF inhibited the expression levels of inflammatory factors and M1 cell polarization after LPS stimulation. Compared with the control group, the number and area of TRAP positive cells, the number and area of bone resorption pit were decreased in rMYDGF intervention group respectively, as well as the area of the F-actin ring was reduced and its shape was incomplete after rMYDGF intervention. Furthermore, rMYDGF reduced the expression levels of osteoclast-specific marker genes and inhibited the phosphorylation of NF-κB signaling pathway protein IκBα during osteoclast differentiation.Conclusion:MYDGF inhibits the inflammatory response and osteoclast differentiation of RAW264.7 cells.
ABSTRACT
Objective:To investigate the effect of alogliptin on bone loss in ovariectomized(OVX)mice.Methods:For animal experiments, thirty 8-week-old C57BL/6J female mice were divided into Sham group, OVX group, and OVX+ alogliptin group. OVX+ alogliptin group were administered with alogliptin in a dosage of 20 mg·kg -1·d -1 by gavage, Sham and OVX groups with equivalent saline. After 12 weeks intervention, serum bone anabolism indicators were detected, and Micro CT and HE staining were used to observe and analyze the bone trabecular structure of femur and tibia in mice. For in vitro experiments, bone marrow mesenchymal stem cells(BMSCs)were incubated with 100 μmol/L alogliptin for osteoblast differentiation. Alkaline phosphatase(ALP)and alizarin red S staining were used to determine the ALP activity and mineralization after osteogenic induction and culture. Real-time fluorescence quantitative PCR and Western blot were used to detect mRNA and protein expressions of osteoblast related genes. Results:Alogliptin intervention improved the biochemical indexes of bone anabolism and protected against bone microstructure deterioration to alleviate bone loss in OVX mice. Alogliptin stimulated osteoblast differentiation and elevated expression levels of Runt-related transcription factor 2(Runx2), ALP, osteocalcin, and osterix in in vitro experiments. Conclusion:Alogliptin can alleviate bone loss in OVX mice.