ULTRAPATHOLOGICAL CHANGES FROM POLYETHYLENE-ABRASION PARTICLES INDUCING OSTEOLYSIS IN A MOUSE AIR-BALLOON BONE-GRAFT MODEL

Yifan Yu^*, Yong Xu, Wei Cai, Wenshan Zuo

Department of Orthopaedics, The Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University, Huai'an 223300, Jiangsu Province, China

Purpose: To explore ultrapathological changes and mechanisms of the impact of polyethylene-wear particles on osteolysis in a mouse air-balloon bone-graft model.

Methods: The sample consisted of 40 mice. Air was injected into mouse chests until the formation met the experiment. In ribs of mice of similar age and weight, a standard airbag was implanted to construct a mouse bone-graft airbag model, and then the modelled mice were divided into a blank control group and a polyethylene wear–particle observation group. Polyethylene particles were injected into the balloon. After 15 days, the balloon tissue and rib tissue were removed and the concentration of inflammatory cytokines and ultrastructural changes in bone-tissue cells determined. Osteolysis and pathological structure were observed with an electron microscope.

Results: The bone-resorption area in the observation group was 236±4.5 nm², which was significantly higher than the control group (167±2.8 nm²), and the number of osteoclasts per unit volume of bone tissue in the observation group was (56±2.6)×10⁴, significantly higher than the (39±1.4)×10⁴ in the control group. Also, the concentration of inflammatory cytokines in the observation group was higher than the observation group.

Conclusions: Polyethylene-wear particles can accelerate the osteolysis of artificial-joint prostheses. Reducing and avoiding solubilisation is the key to preventing bone-graft joint loosening.