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Journal of Osteoporosis
Volume 2012, Article ID 391097, 9 pages
http://dx.doi.org/10.1155/2012/391097
Research Article

Genetic Background Strongly Influences the Bone Phenotype of P2X7 Receptor Knockout Mice

1Departments of Diagnostics and Medicine, Research Centre of Ageing and Osteoporosis, Glostrup University Hospital, 2600 Glostrup, Denmark
2Osteoporosis and Bone Metabolic Unit, Departments of Endocrinology and Clinical Biochemistry, Hvidovre University Hospital, 2650 Hvidovre, Denmark
3Mellanby Centre for Bone Research, The University of Sheffield, Sheffield S10 2TN, UK
4NeuroScience and MedImmune, Milstein Building, Granta Park, Cambridge CB21 6GH, UK
5Department of Internal Medicine, Washington University School of Medicine and St. Louis Veterans Affairs Medical Center, St. Louis, MO 63106, USA
6Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark

Received 31 March 2012; Revised 28 June 2012; Accepted 2 July 2012

Academic Editor: Elena Adinolfi

Copyright © 2012 Susanne Syberg et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The purinergic P2X7 receptor is expressed by bone cells and has been shown to be important in both bone formation and bone resorption. In this study we investigated the importance of the genetic background of the mouse strains on which the P2X7 knock-out models were based by comparing bone status of a new BALB/cJ P2X7−/− strain with a previous one based on the C57BL/6 strain. Female four-month-old mice from both strains were DXA scanned on a PIXImus densitometer; femurs were collected for bone strength measurements and serum for bone marker analysis. Bone-related parameters that were altered only slightly in the B6 P2X7−/− became significantly altered in the BALB/cJ P2X7−/− when compared to their wild type littermates. The BALB/cJ P2X7−/− showed reduced levels of serum C-telopeptide fragment (s-CTX), higher bone mineral density, and increased bone strength compared to the wild type littermates. In conclusion, we have shown that the genetic background of P2X7−/− mice strongly influences the bone phenotype of the P2X7−/− mice and that P2X7 has a more significant regulatory role in bone remodeling than found in previous studies.