Reduced cortical bone mass in mice with inactivation of interleukin-4 and interleukin-13

✍ Scribed by Carl-Johan Silfverswärd; Sune Larsson; Claes Ohlsson; Anders Frost; Olle Nilsson

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 141 KB
• Volume: 25
• Category: Article
• ISSN: 0736-0266
• DOI: 10.1002/jor.20361

✦ Synopsis

Abstract

The aim of the present study was to study the in vivo role of IL‐4 and IL‐13 on bone metabolism. The skeletal phenotypes of male and female IL‐13^−/−^ (n = 7+7), IL‐4^−/−^IL‐13^−/−^ (n = 7+7), and WT (n = 7+7) mice were compared. Analysis was made at 6 weeks of age (juvenile) by pQCT, and at 20 weeks of age (adult) by pQCT, biomechanical testing, and by S‐IGF‐1 and S‐Osteocalcin measurements. The skeletal phenotype was affected only in adult male IL‐4^−/−^IL‐13^−/−^ mice. These animals displayed a reduction in cortical bone mineral content (BMC) of both the tibia and the femur, as measured by mid‐diaphyseal pQCT scans, compared with WT mice (tibia −8.2%; femur −8.5%; p < 0.01). This reduction in cortical BMC was due to a decreased cross‐sectional area as a result of a reduced cortical thickness. The mechanical strength of the cortical bone, tested by three‐point‐bending at the mid‐diaphyseal region of the femurs, demonstrated a significant reduction of displacement at failure (−11.4%), maximal load at failure (−10.6%), and total energy until failure (−29.4%). S‐IGF‐1 and S‐Osteocalcin levels as well as trabecular bone mineral density (tvBMD) were unaffected in adult male IL‐4^−/−^IL‐13^−/−^ mice. IL‐4^−/−^IL‐13^−/−^ male mice show adult onset reduction of cortical bone mass and strength, indicating that the two anti‐inflammatory Th~2~ cytokines IL‐4 and IL‐13 are involved in the regulation of bone remodeling. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 725–731, 2007