Mechanical Properties of Femoral Diaphysis and Femoral Neck of Female Rats Chronically Exposed to Various Levels of Cadmium

Abstract

The effect of chronic exposure to cadmium (Cd) on the mechanical properties of femoral diaphysis and femoral neck was investigated on a rat model of human exposure. Three-week-old female Wistar rats were exposed to Cd in drinking water at concentrations of 1, 5, 50, or 100 mg/L for 12 months. Biomechanical properties of the femoral diaphysis were evaluated in a three-point bending test and those of the femoral neck in a bending test with vertical loading of the head. Bone mineral content (BMC) and bone mineral density (BMD) at the whole femur, and BMD at the diaphysis and proximal femur (head and neck region) of the Cd-treated rats decreased in a dose-dependent manner, except for the diaphyseal BMD at a Cd concentration of 1 mg/L. Exposure to Cd concentrations of 1 and 5 mg/L had only little effect on the diaphyseal mechanical properties (decreased yield load with unchanged bending strength, stiffness, yield stress, ultimate stress, and Young modulus), whereas the bending strength and stiffness of the neck decreased and the yield load clearly tended to decline or declined. The effect of Cd at the two locations was more marked in the 50 and 100 mg/L groups, and changes in the bone geometry were observed in these animals. The results clearly revealed that chronic, even low-level, exposure to Cd results in demineralization and weakening of the femur. The femoral neck seems to be more vulnerable than the diaphysis to failure from Cd. We conclude that environmental exposure to Cd may be an important risk factor for femoral neck fracture.

Cadmium exposure induced itai-itai-like syndrome in male rats

“…Weakening in the bone biomechanical properties, including especially a decrease in the yield and fracture strength, indicates an enhanced bone susceptibility to fracture. Moreover, further study also revealed that cadmium influence cancellous bone and cortical bone mechanical property [5,23]. The rats treated with 1.5mg/kg bw Cd had weakened compression strength and yields strength compared with control which suggested that the L5 and femur became brittle, especially for L5.…”

“…Bone is one of the target organs for cadmium toxicity [1]. It has been shown that cadmium could decrease bone mineral density, result in osteoporosis and increase the risk of bone fracture [2][3][4][5][6][7][8].…”

“…The syndrome is characterized by renal tubular dysfunction and bone damage (osteomalacia, osteoporosis and fracture) and had been found mostly occurred among middle aged and elderly women [5,12]. A markedly increased excretion of urinary molecular weight proteins, such as ß 2-Microglobulin, and high serum alkaline phosphatase (ALP), is found in itai-itai disease patients.…”

“…Pregnancy, lactation, menopause and estrogen depletion caused by menopause might be important factors, both separately and in combination, influencing the bone effects of Cd in women. Recently, some studies in vivo indicated that cadmium may be a weak risk factor for osteoporosis or bone damage in males [5,15]. However, few studies have investigated whether cadmium exposure could induce itai-itai disease in young males.…”

The effect of diet supplementation with propolis and bee pollen on the physicochemical properties and strength of tibial bones in broiler chickens

“…The measurements were taken with an electronic caliper. Based on the geometric characteristics of the tibia, the following parameters were determined as described by Brzóska et al (2005) The content of crude ash and minerals (calcium and phosphorus) in tibial bones was determined after dry mineralization at 650 °C. Ca content was measured by spectrophotometry, and P content was estimated colorimetrically.…”