Weakness in the mechanical properties of the femurs of growing female rats exposed to cadmium.
The study assessed the effect of cadmium (Cd) intoxication on the risk of deformities and fractures of the growing bones of female rats, in order to model human exposure to this metal. For this purpose, bone mineral density and mechanical properties of the proximal and distal ends and diaphysis of the femur were investigated in female Wistar rats exposed to 1, 5 and 50 mg Cd/l in drinking water for 3, 6, 9 and 12 months after the onset of weaning. Daily Cd doses received from drinking water during the treatment period were in the following ranges: 0.059-0.219, 0.236-1.005 and 2.247-9.649 mg/kg body weight at 1, 5 and 50 mg Cd/l, respectively. Biomechanical properties of the femoral proximal and distal ends were evaluated in a compression test, and those of the femoral diaphysis in a cutting test, with loading perpendicular to the longitudinal axis of the bone in all tests. The mineralization and mechanical properties of the bone tissue at various locations on the femur were affected by exposure to Cd in a dose- and duration-dependent manner. Exposure to 1 mg Cd/l (corresponding to low human exposure) during skeletal development weakened the fracture strength of the femoral neck and the trabecular bone at the level of the distal end of the femur and affected the elastic properties of the cortical bone at the femoral diaphysis. At higher levels of Cd exposure, adverse effects were generally observed after a shorter exposure period than for 1 mg Cd/l, and were more advanced. The cadmium-induced weakening of the biomechanical properties of bone at particular sites on the femur correlated with the decreased bone mineralization. The results indicate that even a low exposure to Cd may affect the mineralization and biomechanical properties of growing bone, thus enhancing the risk of fracture.
Department of Toxicology, Medical University of Białystok, Mickiewicza 2c, Białystok 15-222, Poland. mmbr@poczta.onet.pl
Małgorzata M
MM
Brzóska
Katarzyna
K
Majewska
Janina
J
Moniuszko-Jakoniuk
D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D001846:Bone Development / Q000187:drug effects*; D002104:Cadmium / Q000633:toxicity*; D019245:Compressive Strength / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D005269:Femur / Q000187:drug effects* / Q000254:growth & development; D051381:Rats; D017208:Rats, Wistar; D014881:Water Supply; D016474:Weight-Bearing
D004785:Environmental Pollutants; D002104:Cadmium