Bone metabolism of male rats chronically exposed to cadmium

• Published in: Toxicology and applied pharmacology 2005-09, Vol.207 (3), p.195-211
• Main Authors: BRZOSKA, Malgorzata M, MONIUSZKO-JAKONIUK, Janina
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Animals; Biological and medical sciences; Biomarkers; Bone and Bones - drug effects; Bone and Bones - metabolism; Bone Density - drug effects; Bone mineral status; BONE TISSUES; Bone turnover; CADMIUM; Cadmium - toxicity; Calcifediol - metabolism; Calciotropic hormones; CALCITONIN; Calcitonin - metabolism; Calcitriol - metabolism; CALCIUM; Calcium - metabolism; Chemical and industrial products toxicology. Toxic occupational diseases; CHRONIC EXPOSURE; DEMINERALIZATION; DRINKING WATER; Eating - drug effects; ENVIRONMENTAL EXPOSURE; Enzyme-Linked Immunosorbent Assay; FEMUR; Hormones - metabolism; Kidney - drug effects; Kidney - metabolism; Male; Male rats; Medical sciences; METABOLISM; METABOLITES; Metallothionein - metabolism; Metals and various inorganic compounds; PARATHORMONE; PHOSPHATES; Phosphates - metabolism; RATS; Rats, Wistar; Toxicology; VERTEBRAE; VITAMIN D; Weight Gain - drug effects
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2005.01.003

Recently, based on a female rat model of human exposure, we have reported that low-level chronic exposure to cadmium (Cd) has an injurious effect on the skeleton. The purpose of the current study was to investigate whether the exposure may also affect bone metabolism in a male rat model and to estimate the gender-related differences in the bone effect of Cd. Young male Wistar rats received drinking water containing 0, 1, 5, or 50 mg Cd/l for 12 months. The bone effect of Cd was evaluated using bone densitometry and biochemical markers of bone turnover. Renal handling of calcium (Ca) and phosphate, and serum concentrations of vitamin D metabolites, calcitonin, and parathormone were estimated as well. At treatment with 1 mg Cd/l, corresponding to the low environmental exposure in non-Cd-polluted areas, the bone mineral content (BMC) and density (BMD) at the femur and lumbar spine (L1–L5) and the total skeleton BMD did not differ compared to control. However, from the 6th month of the exposure, the Z score BMD indicated osteopenia in some animals and after 12 months the bone resorption very clearly tended to an increase. The rats' exposure corresponding to human moderate (5 mg Cd/l) and especially relatively high (50 mg Cd/l) exposure dose- and duration-dependently disturbed the processes of bone turnover and bone mass accumulation leading to formation of less dense than normal bone tissue. The effects were accompanied by changes in the serum concentration of calciotropic hormones and disorders in Ca and phosphate metabolism. It can be concluded that low environmental exposure to Cd may be only a subtle risk factor for skeletal demineralization in men. The results together with our previous findings based on an analogous model using female rats give clear evidence that males are less vulnerable to the bone effects of Cd compared to females.