title: Effect of sequential treatments with alendronate, parathyroid hormone (1-34) and raloxifene on cortical bone mass and strength in ovariectomized rats.
abstract: Anti-resorptive and anabolic agents are often prescribed for the treatment of osteoporosis continuously or sequentially for many years. However their impact on cortical bone quality and bone strength is not clear.
  
  
  METHODS
  Six-month old female rats were either sham operated or ovariectomized (OVX). OVX rats were left untreated for two months and then were treated with vehicle (Veh), hPTH (1-34) (PTH), alendronate (Aln), or raloxifene (Ral) sequentially for three month intervals, for a total of three periods. Mid-tibial cortical bone architecture, mass, mineralization, and strength were measured on necropsy samples obtained after each period. Bone indentation properties were measured on proximal femur necropsy samples.
  
  
  RESULTS
  Eight or more months of estrogen deficiency in rats resulted in decreased cortical bone area and thickness. Treatment with PTH for 3months caused the deposition of endocortical lamellar bone that increased cortical bone area, thickness, and strength. These improvements were lost when PTH was withdrawn without followup treatment, but were maintained for the maximum times tested, six months with Ral and three months with Aln. Pre-treatment with anti-resorptives was also somewhat successful in ultimately preserving the additional endocortical lamellar bone formed under PTH treatment. These treatments did not affect bone indentation properties.
  
  
  CONCLUSIONS
  Sequential therapy that involved both PTH and anti-resorptive agents was required to achieve lasting improvements in cortical area, thickness, and strength in OVX rats. Anti-resorptive therapy, either prior to or following PTH, was required to preserve gains attributable to an anabolic agent.
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Amugongo
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Yao
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Junjing
authors.initials: J
authors.lastname: Jia
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Dai
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Yu-An E
authors.initials: YA
authors.lastname: Lay
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, CA 95616, USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: Harvey
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Zimmermann
authors.affiliation: Experimental Systems Group, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Schaible
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Dave
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA; Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Ritchie
authors.affiliation: Osteoporosis Research Center, School of Medicine, Creighton University, Omaha, NE 68131, USA.
authors.forename: Donald B
authors.initials: DB
authors.lastname: Kimmel
authors.affiliation: Musculoskeletal Research Unit, Department of Medicine, University of California Davis Medical Center, Sacramento, CA 95817, USA. Electronic address: nelane@ucdavis.edu.
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Lane
mesh_terms: D019386:Alendronate / Q000494:pharmacology*; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D005260:Female; D010052:Ovariectomy; D020849:Raloxifene Hydrochloride / Q000494:pharmacology*; D051381:Rats; D013977:Tibia / Q000187:drug effects / Q000378:metabolism
chemical_list: D020849:Raloxifene Hydrochloride; D019386:Alendronate
keywords: Adult; Indentation; Lamellar bone; MicroCT; Mineralization; Mineralizing surface