title: Effects of bisphosphonates on osteogenesis and osteoclastogenesis signaling during the endochondral ossification of growing rats.
abstract: Osteoclasts and chondroclasts are necessary, during endochondral ossification, for the resorption of primary bone and calcified cartilage septa, respectively. The bisphosphonates inhibit mineralized tissue resorption by various mechanisms according to the different types of this drug, which can affect bone remodeling during skeletal growth. The objective of the present study is to analyze the way that alendronate (ALN) and etidronate (ETN) can affect osteoclastogenesis and bone formation during endochondral ossification of the long bones of growing rats. Newborn Wistar rats were treated daily with ETN, ALN, or sterile saline solution (control) for 21 days. Their femur and tibiae epiphyses were radiographed and analyzed by light, scanning and transmission electron microscopy. The expression of genes related to osteogenesis and to osteoclast differentiation and activity were analyzed by real-time quantitative polymerase chain reaction. The ETN group presented reduced body weight, disorganized growth plate and an extended area of cartilage in the ossification zone with little bone matrix; in the ALN group, this area was not altered. The ALN presented latent TRAP-positive cells, whereas in the ETN group, they were activated. The expression of NFκB1 and 2, OPG, Spp1 and Runx2 in the ossification zone was reduced by both bisphosphonates. RANKL expression was reduced by ETN, whereas ALN decreased the expression of RANK. The results also indicated that, in addition to the anti-resorptive effect of the drugs, disturbances in bone deposition occurred concomitantly with the reduced expression of osteogenesis-related genes.
authors.affiliation: Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Eloiza
authors.initials: E
authors.lastname: Rezende
authors.affiliation: Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, 05508-900, São Paulo, SP, Brazil.
authors.forename: Vivian
authors.initials: V
authors.lastname: Bradaschia-Correa
authors.affiliation: Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Fabio
authors.initials: F
authors.lastname: Siviero
authors.affiliation: Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, 05508-900, São Paulo, SP, Brazil.
authors.forename: Lucas M B
authors.initials: LMB
authors.lastname: Ambrosio
authors.affiliation: Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, 05508-900, São Paulo, SP, Brazil. vearana@usp.br.
authors.forename: Victor E
authors.initials: VE
authors.lastname: Arana-Chavez
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D000071556:Cancellous Bone / Q000187:drug effects / Q000648:ultrastructure; D002452:Cell Count; D004164:Diphosphonates / Q000494:pharmacology*; D005269:Femur / Q000000981:diagnostic imaging / Q000187:drug effects; D005786:Gene Expression Regulation; D006132:Growth Plate / Q000033:anatomy & histology / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D000071681:Tartrate-Resistant Acid Phosphatase / Q000378:metabolism; D013977:Tibia / Q000000981:diagnostic imaging / Q000187:drug effects
chemical_list: D004164:Diphosphonates; D000071681:Tartrate-Resistant Acid Phosphatase
keywords: Alendronate; Bisphosphonate; Bone development; Endochondral ossification; Etidronate