title: Bone biomechanical property deterioration due to tobacco smoke exposure.
abstract: Tobacco smoking has been implicated in the development of osteoporosis and early onset of menopause in women smokers. We measured various biomechanical properties of femurs and tibiae obtained from smoke-exposed and control mice to determine cigarette smoke influences on bone mass, structure, and strength. Growing female C57BL mice were exposed to sidestream cigarette smoke in a whole-body exposure chamber, set at 30 +/- 2 mg smoke particulates/m3 for 4 hours/day and 5 days/week for 12 consecutive weeks. Elevated levels of urinary cotinine and pulmonary ethoxyresorufin deethylase activity in smoke-exposed mice confirmed their effective exposure to cigarette smoke. There were no differences in body weight and physical size (length, medial-lateral and anterior-posterior widths, midshaft cortical area and thickness) of femurs and tibiae between smoke-exposed and control mice. The femoral mid-shaft yield load, stiffness, yield stress, and modulus were, respectively 8%, 13%, 10%, and 14% lower (P < 0.05) in smoke-exposed compared to control mice. The ultimate load and stress in mid-shaft femurs showed decreasing trends (P < 0.1) in smoke-exposed mice. In the femoral neck, the ultimate load and stiffness were 9% and 12% lower (P < 0.05) in smoke-exposed mice, respectively. Further, the ash-to-dry bone weight ratio was smaller ( approximately 6%, P < 0.05), and micro-computed tomographic scanning of distal femoral bone volume/total volume (%) and trabecular thickness showed decreasing trends in smoke-exposed mice compared to the control group. We conclude that exposure to tobacco smoke deteriorates some of the biomechanical properties of bone in growing female mice.
authors.affiliation: Osteoporosis Research Center, Creighton University, Omaha, NE 68131, USA. akhtermp@creighton.edu
authors.forename: M P
authors.initials: MP
authors.lastname: Akhter
authors.forename: A D
authors.initials: AD
authors.lastname: Lund
authors.forename: C G
authors.initials: CG
authors.lastname: Gairola
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D003367:Cotinine / Q000097:blood; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D005260:Female; D005269:Femur / Q000187:drug effects* / Q000503:physiopathology; D008168:Lung / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D013977:Tibia / Q000187:drug effects* / Q000503:physiopathology; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014026:Nicotiana
chemical_list: D014028:Tobacco Smoke Pollution; D019363:Cytochrome P-450 CYP1A1; D003367:Cotinine