title: Influence of early and late zoledronic acid administration on vertebral structure and strength in ovariectomized rats.
abstract: An annual infusion of zoledronic acid (ZOL) reduces fracture risk in osteoporotic patients. Previously, we showed that a single ZOL injection inhibited changes in bone microstructure and strength in rat tibiae after ovariectomy. Here, we determined the effects of a single ZOL injection as preventive and restorative treatment on the bone microstructure and strength in lumbar and caudal vertebrae of ovariectomized (OVX) rats. Twenty-nine female 35-week-old Wistar rats were divided into four groups: SHAM-OVX (n = 9), OVX (n = 5), OVX and early ZOL (n = 8), and OVX and late ZOL (n = 7). ZOL was given once (20 microg/kg body weight s.c.) at OVX in the early ZOL group and 8 weeks later in the late ZOL group; rats were killed 16 weeks after OVX. Trabecular and cortical bone microarchitecture were measured in lumbar (L3) and caudal (Cd6) vertebrae using micro-computed tomography, and compressive mechanical properties were determined in L3 vertebrae. Compared to SHAM-OVX, OVX rats had significantly lower BV/TV; SMI, Tb.N, Tb.Sp, and Conn.D tended to be deteriorated in lumbar vertebrae, while both ZOL groups did not differ from the SHAM-OVX group. Both ZOL groups had significantly higher BV/TV than OVX; the early ZOL group also had significantly lower SMI and higher Tb.Th. OVX tended to decrease mechanical properties, while early and late ZOL treatment inhibited OVX-induced degeneration. Neither OVX nor ZOL induced changes in the trabecular microarchitecture of caudal vertebrae. In summary, in adult rats a single ZOL injection inhibited OVX-induced changes in lumbar vertebral bone microarchitecture and strength.
authors: Eindhoven University of Technology, Den Dolech 2, 5600 MB Eindhoven, The Netherlands. j.e.m.brouwers@tue.nl
authors: Julienne E M
authors: JE
authors: Brouwers
authors: Bert
authors: B
authors: van Rietbergen
authors: Mary L
authors: ML
authors: Bouxsein
mesh_terms: D000818:Animals; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology; D050071:Bone Density Conservation Agents / Q000008:administration & dosage*; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology; D019245:Compressive Strength; D004164:Diphosphonates / Q000008:administration & dosage*; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D013131:Spine / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D000077211:Zoledronic Acid
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates; D007093:Imidazoles; D000077211:Zoledronic Acid