ABSTRACT
Objective To determine the protective effect of osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B (RANK) and RANK ligand (RANKL) on avascular necrosis femoral head.Methods Necrotic tissue or corresponding normal tissues were collected from 29 avascular necrosis femoral head patients.Quantitative Real TimePCR ( qPCR ) is used to evaluate mRNA expression of OPG , RANK and RANKL.OPG and RANKL protein levels were estimated by Western blot.Results The results of qPCR showed that the expression of OPG in the necrotic tissue was significantly higher than that in the normal tissue (4.56 ±0.37) (3.39 ±0.52) (P<0.05).The expression levels of RANKL mRNA in necrotic tissues and normal tissues were (0.86 ±0.11) and (0.31 ±0.08), respectively,the difference was statistically significant (P<0.05).The expression levels of RANK mRNA in necrotic tissues and normal tissmes were(0.87 ±0.12), (0.56 ±0.13) respectively,the difference was statistically significant (P<0.05).The ratio of RANKL/OPG and RANK/OPG in normal tissues were 0.69 and 0.52, respectively.In the necrotic tissues, RANKL/OPG and RANK/OPG ratios were 1.35 and 0.61, respectively.Results of Western blot showed that the expression of OPG in necrotic tissues was consistent with that in normal tissues.The expression of RANKL protein was detected in all samples , and the expression of RANKL protein in necrotic tissue and normal tissue was almost the same.RANK protein expression was not detected in all samples.Conclusion OPG, RANK and RANKL play important roles in progress of bone remodeling in necrotic area and in disturbance of bone homeostasis and might have an effect on bone destruction and subsequent collapse of hip joint.