title: Secondary osteoporosis in collagen-induced arthritis rats.
abstract: Numerous studies have demonstrated that rheumatoid arthritis (RA) is often associated with bone loss; however, few experiments have focused on cancellous and cortical bone changes in rats during the process of arthritis. We have investigated bone changes in rats with collagen-induced arthritis (CIA) and have explored the characteristics of how RA induces osteoporosis by means of bone histomorphometry, bone biomechanics studies, bone mineral density studies, micro computer tomography, enzyme-linked immunosorbant assay, immunohistochemistry, and Western blot analysis. Bone mineral density of the femur and lumbar vertebrae and biomechanical properties of the femur were decreased in CIA rats. Trabecular bone volume of the tibia and lumbar vertebrae was decreased whereas bone resorption was increased in CIA rats. Bone formation of the tibial shaft in periosteal surfaces was decreased in CIA rats. Furthermore, the trabecular bone loss in CIA rats was severer at 16 weeks than at 8 weeks, as was cortical bone loss. The serum level of tumor necrosis factor α in CIA rats was increased, and the expression of dickkopf 1 and that of receptor activator of nuclear factor κB (RANKL) ligand (RANKL) in the ankle joints were also increased, but the expression of osteoprotegerin (OPG) was decreased. We conclude that CIA rats developed systemic osteoporosis, and that osteoporosis became more serious with CIA development. The mechanism may be related to the increase of bone resorption in cancellous bone cause by upregulation of the expression of DKK-1 and regulation of the RANKL/RANK/OPG signaling pathway, and the decrease of bone formation in cortical bone caused by an increase in the expression of DKK-1.
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Qingyun
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Xueting
authors.initials: X
authors.lastname: Xiong
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Xinle
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Wenshuang
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Tie
authors.initials: T
authors.lastname: Wu
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.|Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Liao
authors.initials: L
authors.lastname: Cui
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China.
authors.forename: Yuyu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Pharmacology, Guangdong Medical University, No. 2, Wenming Donglu, Xiashan District, Zhanjiang, 524023, Guangdong, People's Republic of China. xubilianq@126.com.|Guangdong Key Laboratory for Research and Development of Natural Drugs, Guangdong Medical University, Zhanjiang, 524023, Guangdong, People's Republic of China. xubilianq@126.com.
authors.forename: Bilian
authors.initials: B
authors.lastname: Xu
mesh_terms: D000818:Animals; D000843:Ankle Joint / Q000473:pathology; D001169:Arthritis, Experimental / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D001696:Biomechanical Phenomena; D015519:Bone Density; D000071556:Cancellous Bone / Q000473:pathology; D005260:Female; D005269:Femur / Q000503:physiopathology; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D010024:Osteoporosis / Q000209:etiology* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D053244:Osteoprotegerin / Q000378:metabolism; D053245:RANK Ligand / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew
chemical_list: C531384:Dkk1 protein, rat; D036341:Intercellular Signaling Peptides and Proteins; D053244:Osteoprotegerin; D053245:RANK Ligand; C506032:Tnfrsf11b protein, rat
keywords: Collagen-induced arthritis; Histomorphometry; Osteoporosis; Rat; Rheumatoid arthritis