Bone Abstracts

Aim of the study: Animal studies have also been reported demonstrating enhanced development of osteomalacia and increased osteoids following long-term high-dose administration of Al compound in rats, especially in those with renal failure rats (Robertson et al.).

For histologic detection of Al. aluminon and other staining reagents have usually been used but are not adequately sensitive and lack in specificity. We have recently developed a method for directly observing Al distribution in bone tissues with a laser microscope on bone sections stained with lumogallion, an o, p,o-trihydroxyazo compound as a highly sensitive, specific fluorescent reagent.

Material and methods: Renal failure rats were administered Al compounds orally and parenterally. Animals were sacrificed under anesthesia,the ilium and femora excised were immediately fixed, the bone sections were stained with lunogallion,and examined with confocal laser scanning microscope.

Results: The femur from a 5/6-nephrectomized rat given physiological saline as a control showed an Al content of 5.20 ppm. In the fluorescent micrographs of control femora, the bone was largely ossified with some osteoids between calcified areas but showed no aluminum deposition. Fluorescent micrographs of the femur from 5/6-nephrectomized rats treated orally and intraperitoneally with 5% K2Al2SO4 for 6 months showed broad zones of osteoids between ossified areas, with a diffuse or restiform distribution of aluminum coaguration within the osteoids. The findings are indicative of an abnormal accumulation of Al in the osteoids.

Conclusion: The present observation disclosed that, Al distributed diffusely or as aggregates at high concentration in osteoid tissues.