Roles of OPG and OPGL in periprosthetic osteolysis / 中华创伤骨科杂志

ABSTRACT

Objective To investigate the histological and biochemical responses associated with periprosthetic osteolysis,including the changes of tumor necrosis factor-?(TNF-?),osteoprotegerin(OPG) and os- teoprotegeria ligand (OPEL) in the interface membrane in rat models so as to understand the mechanisms of these interactions.Methods Twenty-four male SD rats were used in this study.A titanium alloy plug was inserted into each distal femur through the knee joint.Polyethylene particles were injected into the left knee at 2,4,6,8 and 10 weeks after implantation of the plugs.Saline solution was injected into the right knee as the control.The animals were killed 12 weeks after implantation.The distal femur was taken from each knee to make histological sections. The samples were made decalcified and stained with hematoxylin and eosin.The histopathological changes were observed under a light microscope.The concentrations of TNF-?in the membrane were assayed by a ELISA kit and the mRNA expressions of OPG and OPEL extracted from the tissue around the plug were detected by RT-PCR. Results The interface membrane taken from the experimental side was found to contain extensive fibrous tissues which extended deeply into the surrounding hone.TNF-?concentrations in the membrane of the experimental side were higher than in the control membrane.There was a significant decrease of OPG mRNA and a significant increase of OPGL mRNA in the membrane around the plug at the experimental side compared with the control side.Con- clusions Polyethylene particles can induce inflammatory responses around the titanium alloy plug.The increase of OPGL expression and reduction of OPG expression in membrane at the experimental side may be induced by TNF-?. Such changes might contribute to the differentiation of osteoclasts and result in the periprosthetic osteolysis.