Histochemical staining of bone aluminum: comparison of aluminon and acid solochrome azurine and their correlation with bone aluminum content.

Aluminum (Al) may be a pathogenic factor in dialysis associated osteodistrophy. Aluminon and Acid Solochrome Azurine have been used for the detection of Al deposits in bone. We compared Aluminon and Acid Solochrome Azurine stains in normal (N) and uremic (U) rats. Both received intraperitoneal injections of aluminum chloride (AlCl3), until a cumulative dose of 5 mg/Al (NAL5; UAL5) or 30 mg/Al (NAL30; UAL30). The control groups received an equal volume of distilled water by means of intraperitoneal injections. Histomorphometric analysis showed that formation parameters (osteoid volume-OV/BV and osteoid surface-OS/BS), were significantly greater in the uremic groups than the control groups. In addition, the aluminum intoxication increased these values. When we compared the aluminum deposits in the undecalcified bone detected by both staining methods, we observed that Acid Solochrome Azurine was more sensitive than Aluminon in the normal renal function group and uremic treated with 5 mg of AlCl3. All our results were compared with atomic absorption spectrophotometry, showing that Al content presented a positive correlation with Aluminon stain in U and N rats, nevertheless it was not observed using Acid Solochrome Azurine stain. We conclude that histochemistry is important in diagnosing and monitoring aluminum bone disease.