Effects of chronic inflammation on bone in mice

Timed‐pregnant C57BL6 mice were procured from Charles River Laboratories and fed a selenium‐deficient diet from the final days of gestation through lactation. At 24 days of age, pups were weaned and randomly assigned to one of four dietary treatments (Se of 0.02, 0.2, 2.0 or 4.0 mg/kg diet). At 96–98 days of age mice were randomly assigned to placebo or lipopolysaccharide (E. coli Serotype 0127:B8) treatments. A LPS pellet designed to produce chronic inflammatory stress (release of 0.1 μg LPS/g body weight per day) was inserted subcutaneously and remained in place until necropsy (28 days). Evaluations of dietary selenium effects are continuing but LPS significantly affected bone parameters. Body weight was reduced by LPS 14 days after implantation but differences were no longer significant by 28 days. Bone mineral density of lumbar vertebra 3 (L 3 )and L 4 (measured by Piximus) was significantly reduced by LPS. Microarchitecture of trabecular bone was analyzed in L 4 using microcomputed tomography (Scanco MicroCT 40). Bone volume/total volume, connectivity density, and trabecular number were all significantly reduced by LPS treatment. The structural model index and trabecular separation were increased by LPS treatment. Chronic inflammation at a level that does not produce severe body weight loss still significantly impaired measures of bone microarchitecture. (Supported by Oklahoma Center for Advancement of Science and Technology).