title: [Effect of icariin on bone destruction and serum RANKL/OPG levels in type II collagen-induced arthritis rats].
abstract: OBJECTIVE
  To observe the effect of Icariin (ICA) on serum receptor activator of NFkappaB-ligand (RANKL)/osteoprotegerin (OPG) production and bone destruction in type II collagen-induced arthritis (CIA) rats.
  
  
  METHODS
  The CIA rat model was established in all rats, except those in the normal group (n = 8) using bovine type II collagen and complete Freund's adjuvant. Totally 24 CIA rats with arthritis index (AI) > or = 6 were selected and divided into the model group, the methotrexate (MTX) group, and the ICA group according to the AI score, 8 in each group. Normal saline was given to rats in the normal group and the model group by gastrogavage. MTX at the weekly dose of 5 mg/kg was given to rats in the MTX group. ICA at the daily dose of 20 mg/kg was given to rats in the ICA group. All medication lasted for 4 weeks. The AI scores were recorded once a week. Histomorphologic changes of the ankle joint were observed by HE staining. The bone destruction and the osteoporosis of the foot phalanx were detected by X-ray. Serum levels of RANKL and OPG were determined by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  After 4-week intervention, when compared with the model group, AI score and Larsen score were significantly lower, the serum RANKL concentration and the RANKL/OPG ratio obviously decreased, while the serum OPG concentration obviously increased in the CIA group (P < 0.05, P < 0.01). In the MTX group, the aforesaid indices decreased, but without statistical difference (P > 0.05). Results of HE staining indicated that hyperplasia of joint synovium, infiltration of inflammatory cells, and the degree of articular cartilage destruction were obviously alleviated in the ICA group.
  
  
  CONCLUSIONS
  ICA could alleviate or lessen the degree of articular cartilage destruction in CIA rats, and its mechanism might be associated with reducing serum levels of RANKL and elevating levels of OPG, thus further decreasing the ratio of RANKL/OPG.
authors.affiliation: Basic Medicine Department of Rehabilitation, Rehabilitation College, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
authors.forename: Yi-Jie
authors.initials: YJ
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.forename: Dong-Yi
authors.initials: DY
authors.lastname: He
authors.forename: Qiao-Qiao
authors.initials: QQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000097:blood* / Q000473:pathology; D024043:Collagen Type II / Q000009:adverse effects; D005260:Female; D005419:Flavonoids / Q000494:pharmacology*; D053244:Osteoprotegerin / Q000097:blood*; D053245:RANK Ligand / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D024043:Collagen Type II; D005419:Flavonoids; D053244:Osteoprotegerin; D053245:RANK Ligand; C506032:Tnfrsf11b protein, rat; C056599:icariin