Inhibitory effect of icariin on Ti-induced inflammatory osteoclastogenesis.

BACKGROUND: Wear particle-induced periprosthetic osteolysis that results in aseptic loosening is the most common cause of long-term failure after total joint replacement. MATERIALS AND METHODS: Icariin (ICA), a flavonoid isolated from Epimedium pubescens, inhibits osteoclast formation, but its effects on wear particle-induced inflammatory osteoclastogenesis remains unclear. We investigated the role of ICA in the regulation of osteoclast differentiation in a murine macrophage cell line (RAW264.7), which is stimulated by titanium (Ti) particles and the receptor activator of NF-κB ligand. RESULTS: ICA effectively inhibited osteoclast formation and bone resorption in the differentiation medium. ICA (10(-7) mol/L) significantly reduced the number of tartrate-resistant acid phosphatase-positive cells compared with the control, and significantly reduced the percentage of the surface covered by resorption lacunae. Quantitative real-time polymerase chain reaction analysis showed that ICA inhibited messenger RNA expression for the receptor activator of nuclear factor-κB, cathepsin K, tartrate-resistant acid phosphatase-positive, and matrix metalloproteinase-9 in RAW264.7 cells stimulated by Ti particles and receptor activator of NF-κB ligand. ICA also reduced pro-inflammatory cytokine expression of interleukin-1ß and tumor necrosis factor-α in RAW264.7 cells cultured with Ti particles. In addition, incubation with cholecystokinin-8 showed that ICA had no toxic effects on RAW264.7 cells. CONCLUSIONS: ICA possibly elicited inhibitory effects on inflammatory osteoclastogenesis induced by Ti particles, indicating that ICA may be useful for the prevention and treatment of wear particle-induced osteolysis.

[Long term outcome of posterior lumbar pedicle screw fixation combined with isthmic bone graft fusion in the treatment of lumbar spondylolysis in young patients].

OBJECTIVE: To investigate the long-term effect of posterior lumbar pedicle screw fixation combined with isthmus bone grafting and fusion in young patients with spondylolysis. METHODS: A retrospective study was carried out, consisting of 16 young patients with lumbar spondylolysis without spondylolisthesis treated by lumbar posterior pedicle screw fixation combined with isthmic bone grafting fusion from January 2006 to July 2014. There were 11 males and 5 females, aged from 18 to 21 years old, with an average age of 19.3 years old, and the course of disease ranged from 12 to 26 months, with an average of 22 months. All the patients suffered from lumbar pain and difficulty in getting out of bed. Preoperative CT confirmed 12 cases of L5 isthmus fissure and 4 cases of L4 isthmus fissure. Bone graft fusion was confirmed and internal fixation was removed after operation. Lumbar spondylolysis was evaluated by lumbago visual analogue scoring method at preoperative and postoperative time points. Lumbar isthmic fusion was evaluated by lumbar CT, and degeneration of fixed and adjacent segments of lumbar intervertebral disc was evaluated by lumbar MRI. RESULTS: Of the 16 patients, 13 patients (26 sides) were followed up, with a mean duration of 96 months. The operation time ranged from 80 to 105 minutes, with an average of 95 minutes. The intraoperative bleeding volume ranged from 150 to 300 ml, with an average of 225 ml. All the patients were successfully operated without any complications related to the operation. VAS scores at each time point after operation were improved compared with those before operation(P<0.01). Postoperative CT scans of lumbar spine showed osseous fusion at 6 to 14 months, with an average of 12 months. There were no changes of adjacent segment degeneration, fixed segment disc degeneration and protrusion on lumbar spine MRI, and no symptomatic recurrence or recurrent spondylolysis in the long term. CONCLUSIONS: The posterior lumbar pedicle screw fixation combined with isthmic bone grafting and fusion is safe and effective in the treatment of young spondylolysis. The fusion rate is high and the interference of normal physiological range is reduced. The long-term effect is satisfactory.

Icariin protects against titanium particle-induced osteolysis and inflammatory response in a mouse calvarial model.

Periprosthetic osteolysis and subsequent aseptic loosening are common in implant failure, a complication with revision surgery being the only established treatment. Wear particle-induced inflammation and extensive osteoclastogenesis play critical roles in periprosthetic osteolysis. A recent approach in limiting osteolysis is therefore focused on inhibiting osteoclastic bone resorption. This study aimed to investigate the potential impact of icariin, the major ingredient of Epimedium, on titanium particle-induced osteolysis in a mouse calvarial model. Eighty-four male C57BL/J6 mice were divided randomly into four groups. Mice in the sham group underwent sham surgery only, whereas animals in the vehicle, low- and high-concentration icariin groups received titanium particles. Mice in the low- and high-concentration icariin groups were gavage-fed with icariin at 0.1 or 0.3 mg/g/day, respectively, until sacrifice. Mice in the sham and vehicle groups received phosphate-buffered saline daily. After 2 weeks, mouse calvariae were collected for micro-computed tomography, histomorphometry and molecular analysis. Icariin significantly reduced particle-induced bone resorption compared with the vehicle group. Icariin also prevented an increase in receptor activator of nuclear factor kappa B ligand/osteoprotegerin ratio and subsequently suppressed osteoclast formation in titanium particle-charged calvariae. In addition, immunohistochemical analysis and enzyme-linked immunosorbent assay showed icariin significantly reduced expression and secretion of tumor necrosis factor-α, interleukin-1ß and interleukin-6 in the calvariae of titanium-stimulated mice. Collectively, these results suggest that icariin represents a potential treatment for titanium particle-induced osteolysis and could be developed as a new therapeutic candidate for the prevention and treatment of aseptic loosening.

Strontium ranelate inhibits titanium-particle-induced osteolysis by restraining inflammatory osteoclastogenesis in vivo.

Wear-particle-induced osteolysis is considered to be the main reason for revision after arthroplasty. Although the exact mechanism remains unclear, inflammatory osteoclastogenesis plays an important role in this process. Strontium ranelate (SR) was found to have a therapeutic effect on osteoporosis in postmenopausal women. Based on prior studies, the present authors hypothesized that SR prevents wear-particle-induced osteolysis through restraining inflammatory osteoclastogenesis. The present study used 80 male C57BL/J6 mice to test this hypothesis in a murine osteolysis model. All experimental animals were randomly divided into four groups: a control group; a SR group; a titanium group; and a titanium+SR group. Once titanium particles had been implanted in mice, the mice were administered SR (900 mg kg(-1) day(-1)) by gavage for 14 days. After 14 days, the calvaria were collected for micro-computed tomography (µCT), histological and molecular analysis. The results of µCT and histomorphometric analysis demonstrated that SR markedly inhibited bone resorption and the generation of tartrate-resistant acid-phosphatase-positive cells in vivo, compared with titanium-stimulated calvaria. Reverse transcription polymerase chain reaction and ELISAs showed that SR stimulated the mRNA and protein expression of osteoprotegerin, and inhibited gene and protein expression of receptor activators of nuclear factor-kappa B ligand in titanium-particle-charged calvaria. In addition, SR obviously reduced the secretion of tumor necrosis factor-α and interleukin-1ß in the calvaria of the titanium group. It was concluded that SR inhibits titanium-induced osteolysis by restraining inflammatory osteoclastogenesis, and that it could be developed as a new drug to prevent and treat aseptic loosening.