Age-related changes of element contents in human tendon of the iliopsoas muscle and the relationships among elements.

To elucidate compositional changes of the tendons with aging, the authors investigated age-related changes of element contents in the tendon of the iliopsoas muscle by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 14 men and 14 women, ranging in age from 4 to 102 yr. The insertion tendons of the iliopsoas were removed from the cadavers after ordinary dissection and also surgically from patients with congenital dislocation of the hip. It was found that both Mg and P in the tendon of the iliopsoas muscle increased significantly with aging, but the other elements, such as S, Ca, Na, Zn, Fe, and Si, hardly changed with aging. With regard to the relationship among element contents, extremely significant correlations were found between P and S contents, between Mg and Na contents, and between S and Zn contents. In addition, very significant correlations were found between Si and either S or Zn contents. However, there was no significant correlation between Ca and P contents. These results revealed that with regard to age-related changes of element contents and the relationships among element contents, the tendon of the iliopsoas muscle was different from the Achilles tendon, in which both Mg and P decreased significantly with aging and there were significant correlations each other among the contents of S, Mg, and P.