ABSTRACT
Objective To study the effect of icariin on proliferation and phenotype of osteoblasts interfered with titanium particles. Methods Calvarial osteoblasts of newborn rats were cultured in vitro and cell identification was performed by alkaline phosphatase staining. Effect of titanium particles with different concentrations on osteoblasts proliferation was detected by CCK-8 method. Meanwhile , medium lethal concentration of titanium particles was screened out. Under this concentration , icariin with concentrations of 10-5, 10-6, 10-7, 10-8, 10-9 and 10-10 mol/L was added respectively for interference. The effect of icariin on proliferation of osteoblasts interfered with titanium particles was observed so as to obtain optimum drug concentration. Icariin with optimum concentraion was added into osteoblasts interfered with titanium particles. ALP activity of each group was detected by ELISA and calcified nodules were stained by alizarin S red to observe the effect of icariin on phenotype of osteoblasts. Results Titanium particles with different concentrations can inhibit proliferation of osteoblasts (P < 0.05), 0.5 mg/mL is its medium lethal concentration. Icariin can promote proliferation of osteoblasts interfered with particles (P < 0.05), the optimum drug concentration is 10-9 mol/L. With this concentration, icariin can significantly improve ALP activities of osteoblasts (P<0.05) and calcified nodules formation. Conclusion Icariin can promote proliferation and phenotypic expression of osteoblasts interfered with titanium particles. It may probably become an effective medicine for preventing aseptic joint prosthesis loosening.
ABSTRACT
Wear particles are phagocytosed by macrophages and other inflammatory cells, resulting in cellular activation and release of proinflammatory factors, which cause periprosthetic osteolysis and subsequent aseptic loosening, the most common causes of total joint arthroplasty failure. During this pathological process, tumor necrosis factor-alpha (TNF-α) plays an important role in wear-particle-induced osteolysis. In this study, recombination adenovirus (Ad) vectors carrying both target genes [TNF-α small interfering RNA (TNF-α-siRNA) and bone morphogenetic protein 2 (BMP-2)] were synthesized and transfected into RAW264.7 macrophages and pro-osteoblastic MC3T3-E1 cells, respectively. The target gene BMP-2, expressed on pro-osteoblastic MC3T3-E1 cells and silenced by the TNF-α gene on cells, was treated with titanium (Ti) particles that were assessed by real-time PCR and Western blot. We showed that recombinant adenovirus (Ad-siTNFα-BMP-2) can induce osteoblast differentiation when treated with conditioned medium (CM) containing RAW264.7 macrophages challenged with a combination of Ti particles and Ad-siTNFα-BMP-2 (Ti-ad CM) assessed by alkaline phosphatase activity. The receptor activator of nuclear factor-κB ligand was downregulated in pro-osteoblastic MC3T3-E1 cells treated with Ti-ad CM in comparison with conditioned medium of RAW264.7 macrophages challenged with Ti particles (Ti CM). We suggest that Ad-siTNFα-BMP-2 induced osteoblast differentiation and inhibited osteoclastogenesis on a cell model of a Ti particle-induced inflammatory response, which may provide a novel approach for the treatment of periprosthetic osteolysis.