Dissolution of nickel and tissue response observed by X-ray scanning analytical microscopy

The recently developed X-ray scanning analytical microscope (XSAM) was applied for the analysis of the soft tissue of rat in which Ni was implanted and serious inflammation occurred. Our aim is to investigate the relationship between tissue response and elemental distributions. The XSAM observation was conducted in air without pretreatment and staining of samples. Mapping images of P, S, Ca, Fe and Ni, which were the elements with low concentration in soft tissue, were obtained from the soft tissue blocks of rat where Ni was implanted. S mapping image showed the localization of S in muscle and in hairs. Ca mapping image showed the localization of Ca in muscle and hair roots. Fe distribution was also observed and the localized area was consistent with the hemorrhagic area. The Ni dissolution area was clearly detected around the Ni implant. Comparison with the histological observation showed that the Ni dispersed area was consistent with the inflammatory area and the degree of tissue damage was closely related to the dissolved Ni concentration.