Reduced cortical bone mass in mice with inactivation of interleukin-4 and interleukin-13.
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.
Silfverswärd
Carl-Johan
CJ
Department of Surgical Sciences, University of Uppsala, S-751 85 Uppsala, Sweden.
Larsson
Sune
S
Ohlsson
Claes
C
Frost
Anders
A
Nilsson
Olle
O
D000818:Animals; D015519:Bone Density / Q000276:immunology*; D016723:Bone Remodeling / Q000276:immunology; D001862:Bone Resorption / Q000000981:diagnostic imaging / Q000276:immunology* / Q000503:physiopathology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000276:immunology / Q000503:physiopathology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D018793:Interleukin-13 / Q000235:genetics*; D015847:Interleukin-4 / Q000235:genetics*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D015675:Osteocalcin / Q000097:blood; D010052:Ovariectomy; D010641:Phenotype; D013977:Tibia / Q000000981:diagnostic imaging / Q000276:immunology / Q000503:physiopathology; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing
D018793:Interleukin-13; D015675:Osteocalcin; D015847:Interleukin-4; D007334:Insulin-Like Growth Factor I