Age-related elemental change in bones

To investigate age dependence of the bone element contents and structure, lumbar and femur from Sprague-Dawley (SD) rats were chosen for their more susceptibility to fracture. These rats were divided into to 5 age groups: 1, 4, 7, 11 and 25 month-age, corresponding human beings from the young to the old. The elements contents were detected by external Proton Induced X-ray emission (PIXE) technique. X-ray Absorption Fine Structure (XAFS) method was also applied to obtain information about calcium (Ca) and phosphor (P) structure. It was found that Ca content, Ca/P ratio, valance state of Ca and P and their coordinate structure remains unaltered with age variance, whereas the content of strontium (Sr) was significantly decreasing. Sr concentration may provide a new parameter for diagnosis of bone disorder