Staining for histologic diagnosis of aluminum osteopathy--application of confocal laser scanning microscopy to observation for offminum in bones from aluminum-treated, subtotally nephrectomized rats.

To histologically detect excess aluminum (Al) taken up by bones in a rat model of renal failure prepared by 5/6-nephrectomy, non-decalcified bone tissue sections from specimens of the tibia, femur, rib and ilium were stained with a newly developed lumogallion reagent and examined for aluminum by confocal laser scanning microscopy. The assay revealed that Al contents in the tibia and femur of Al-treated rats tended to be a few-fold higher, compared to controls. With the lumogallion stain technique, Al in bones could be detected and identified at Al concentrations of > or = 9.0 micrograms/g in bone tissues. The reaction of the metal with lumogallion is specific and proved to be positive even at concentrations of excess Al so low as to be undetectable by conventional methods. The present observation disclosed that, unlike the generally accepted view, the Al was accumulated not in the calcification front but was distributed diffusely or as aggregates at high concentration in osteoid tissues. Z mode scans of the slides permitted steric delineation of the state of Al accumulation in bone tissues. The method described herein is considered a useful means for clinical diagnosis of aluminum osteopathy.