Aging effects of major and trace elements in rat bones and their mutual correlations

The concentrations of 29 major to trace elements in rat bones (femur) aging from 5 to 113 weeks old were determined. The samples were decomposed by high purity nitric acid and hydrogen peroxide. Nine elements (Na, Mg, P, K, Ca, Fe, Ni, Zn, and Sr) were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and 20 elements (Li, B, Al, V, Cr, Mn, Cu, As, Se, Rb, Mo, Ag, Cd, Sb, Cs, Ba, W, Tl, Pb, and U) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Aging effects on these elements and mutual elemental correlations were investigated. The concentrations of Ca, P and Na increased in the initial stage of 5-17 weeks and then maintained constant values, whereas those of Mg, K, Mn, Sr and Ba showed decreasing trends of differing patterns. Furthermore, Cu, Zn and Mo showed increasing trends for a whole range of ages. Selenium showed a remarkable increasing trend with a factor of 10. The values of Na, Mg, P, K, Ca, Mn, Cu, Zn, Se and Mo in the age-matched rats distributed narrow ranges, indicating that the metabolism of these elements in bone was well-established. By contrast, those of Al, V, Ni, Ag, Cd, Sb, W, Tl, and U were distributed across a broad range. The metabolism of these elements was not well-established. A cluster analysis was performed using an elemental correlation matrix.