Effect Of Inhibition Of Cyclosporine A On PMMA Particle-induced Bone Resorption

Osteolysis around knee and hip implants that subsequently leads to aseptic loosening has become a major clinical problem, and occurs in association with the formation of wear debris. Recent studies show wear debris such as ultra-high- molecular- weight polyethylene particle, polymethylmethacrylate particle, kinds of meral particle have an significant role in osteolysis. Wear particles enter the periprosthetic tissue where they are phagocytosed by macrophages,foreign-body giant cell, fibroblast,osteoclast,. These cells then release an array of cytokines, such as, IL-1, IL-6, PGE-2, TNF-αand other mediators of inflammation that lead to the development of an inflamed granulomatous tissue adjacent to the bone. Eventually, osteoclasts are recruited and/or activated to resorb the bone leading to osteolysis and eventually loosening of the prosthesis. In this article, we evaluate the effect of cyclosporine A on the particle-induced osteoclast formation and function, and cyclosporine A may be one of effective medicine for clinical treatment of aseptic loosening.PartⅠAn experimental study of polymethylmethacrylate particle induced the periprosthetical osteolysis Objective:To study the mechanism of particle-induced periprosthetic osteolysis with the culture of osteoclast in vitro. Methods: Under the stimulation by polymethylmethacrylate(PMMA) particles, SD rat bone marrow cells were cultured in vitro. The cells were stained with TRAP to observe the morphological variety; The bone resorption pits on bone slices were stained by toluidine blue and the number of the bone resorption pits was counted. Results: PMMA particles induced more TRAP positive osteoclast and bone resorption pits than the control group in vitro. Conclusion:PMMA particles can induce periprosthetic osteolysis, and then lead to aseptic loosening.PartⅡInhibition of cyclosporineA on osteoclast formation and function induced by polymethylmethacrylate particleObjective:To evaluate the effect of cyclosporine A on the article-induced osteoclast formation and function. Methods: After SD rat bone marrow cells were taken and washed withα-MEM nutrient solution in which no serum contained, cells were gathered and re-suspended inα-MEM nutrient solution with 100ml/L fetal bovine serum. The cell suspension in 1.5×107/ml concentration was made after counting. Under the induction by PMMA particles, the cells were cultured for two weeks in the presence of 10-8mol/L,10-7mol/L,10-6 mol/L cyclosporine A. Meanwhile, the positive and negative control group was set up. Osteoclast formation was detected by TRAP staining and its function was assessed by absorption lacuna using electron microscope. Results: Large osteoclasts and absorption lacuna were formed under the induction of PMMA particles. Osteoclast formation were partially inhibited adding in 10-8mol/L,10-7mol/L cyclosporine A , and no TRAP positive osteoclast formed adding in 10-6mol/L cyclosporineA. The absorption lacuna was partial fewer adding in 10-8mol/L cyclosporine A than that of positive control group, and no absorption lacuna was found at the high dose of cyclosporine A(10-7mol/L,10-6mol/L). Conclusion:Cyclosporine A has obviously inhibition to osteoclast formation and has a dose-dependence manner.PartⅢInhibition of cyclosporine A on PMMA particle-induced bone resorption in vivoObjective: To study the mechanism of cyclosporineA inhibite particle- induced periprosthetic osteolysis by the murine calvarial osteolysis model. Methods: Sixty BALB/c mice were divided into five groups of 12 and treated according to the following protocol for 2 weeks:Group A as the control group,α-MEM without PMMA particle was used on the surface of the calvaria and received 1ml saline by intraperitoneal injection daily; Group B PMMA particle suspended solution was used on the surface of the calvaria and received 1ml saline by intraperitoneal injection daily; Group C PMMA particle suspended solution was used on the surface of the calvaria and received CsA 2mg/kg by intraperitoneal injection daily; Group D PMMA particle suspended solution was used on the surface of the calvaria and received CsA 4mg/kg by intraperitoneal injection daily; Group E PMMA particle suspended solution was used on the surface of the calvaria and received CsA 8mg/kg by intraperitoneal injection daily; Calvarias were harvested after two weeks, then embedded in paraffin, and stained with hematoxylin-eosin, tartrate-resistant acid phosphatase. Results: PMMA particle induced more osteolytic effect thanα-MEM control. Cyclosporine A 4mg/kg and 8mg/kg may significantly inhibit the osteolytic effect of the PMMA particle and the Cyclosporine A 8mg/kg has a stronger inhibiting effects than the Cyclosporine A 4mg/kg in the same dose. Conclusion:Cyclosporine A has significant inhibiting effects on the bone resorption of murine calvaria induced by PMMA particle.With the upper three experiments, we believe that Cyclosporine A has promised a wonderful use for clinical treatment of periprosthetic osteolysis and can prevent aseptic loosening.