Inhibitory Effects of Lanthanum Chloride on Wear Particle-Induced Osteolysis in a Mouse Calvarial Model

Copper modified cobalt-chromium particles for attenuating wear particle induced-inflammation and osteoclastogenesis

The nature of aseptic prosthetic loosening mainly relates to the wear particles that induce inflammation and subsequent osteoclastogenesis. The ideal approach to impede wear particle-induced osteolysis should minimize inflammation and osteoclastogenesis. In this work, Co29Cr9W3Cu particles were used as a research model for the first time to explore the response of Co29Cr9W3Cu particles to inflammatory response and osteoclast activation in vitro and in vivo by using Co29Cr9W particles as the control group. In vitro studies showed that the Co29Cr9W3Cu particles could promote the generation of M2-phenotype macrophages and increase the expression level of anti-inflammatory factor IL-10, while inhibiting the formation of M1-phenotype macrophages and down-regulating the expression of inflammatory factors TNF-α, IL-6 and IL-1β; More importantly, the Co29Cr9W3Cu particles reduced the expression of NF-κB and downstream osteoclast related-specific transcription marker genes, such as TRAP, NFATc1, and Cath-K; In vivo results indicated that the Co29Cr9W3Cu particles exposed to murine calvarial contributed to decreasing the amount of osteoclast and osteolysis area. These findings collectively demonstrated that Cu-bearing cobalt-chromium alloy may potentially delay the development of aseptic prosthetic loosening induced by wear particles, which is expected to provide evidence of Co29Cr9W3Cu alloy as an alternative material of joint implants with anti-wear associated osteolysis.

[Establishment of artificial joint aseptic loosening mouse model by cobalt-chromium particles stimulation]

Objective

To explore the feasibility of establishment of a artificial joint aseptic loosening mouse model by cobalt-chromium particles stimulation.

Methods

Twenty-four 8-week-old male severe combined immunodeficient (SCID) mice were divided into experimental group ( n=12) and control group ( n=12). The titanium nail was inserted into the tibial medullary cavity of mouse in the two groups to simulate artificial joint prosthesis replacement. And the cobalt-chromium particles were injected into the tibial medullary cavity of mouse in experimental group. The survival of the mouse was observed after operation; the position of the titanium nail and the bone mineral density of proximal femur were observed by X-ray film, CT, and Micro-CT bone scanning; and the degree of dissolution of the bone tissue around the tibia was detected by biomechanical test and histological staining.

Results

Two mice in experimental group died, and the rest of the mice survived until the experiment was completed. Postoperative imaging examination showed that there was no obvious displacement of titanium nails in control group, and there were new callus around the titanium nails. In experimental group, there was obvious osteolysis around the titanium nails. The bone mineral density of the proximal tibia was 91.25%±0.67%, and the maximum shear force at the tibial nail-bone interface was (5.93±0.85) N in experimental group, which were significantly lower than those in control group [102.07%±1.87% and (16.76±3.09) N] ( t=5.462, P=0.041; t=3.760, P=0.046). Histological observation showed that a large number of inflammatory cells could be seen around the titanium nails in experimental group, while there was no inflammatory cells, and obvious bone tissue formation was observed in control group.

Conclusion

The artificial joint aseptic loosening mouse model can be successfully established by cobalt-chromium particles stimulation.

11R-VIVIT Peptide Inhibits Calvaria Osteolysis Induced by Experimental Design

Wear particles released from prosthetic implants can cause periprosthetic osteolysis, a major cause of implant loosening. The aim of this study was to investigate the effects of the 11R-VIVIT peptide on osteolysis induced by titanium (Ti) particles in vivo. Twenty-four C57BL/J6 mice were divided into 3 groups: sham operation, Ti group, and Ti/VIVIT group. A calvarial osteolysis model was established by implanting Ti particles into mouse calvaria of the Ti and Ti/VIVIT groups. After 2 weeks, 11R-VIVIT peptide (10 mg/kg/day) was intraperitoneally injected into the mice of the Ti/VIVIT group for 14 days. The other 2 groups received saline injection. The calvarial specimens were removed and stained with van Geison staining. The calvarial sagittal suture area was measured to observe bone resorption. The calvarial new bone area was measured to observe bone formation. Compared with the sham group, the area of calvarial new bone and calvarial sagittal suture were higher in the Ti group (P < 0.01). Compared with the Ti group, the area of calvarial new bone was higher and the area of calvarial sagittal suture was lower in the Ti/VIVIT group (P < 0.01). In conclusion, the 11R-VIVIT peptide inhibited bone resorption and enhanced bone formation. This may have contributed to lower wear particle-induced osteolysis. This method could eventually be used to prevent prosthesis loosening after joint replacement and to prolong the life of the prosthesis.