Reactivation of inhibited bone acid phosphatase and its significance in bone histomorphometry

C. C. Liu, D. J. Sherrard, N. A. Maloney, G. A. Howard

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Despite biochemical demonstration of acid phosphatase (AcP) activation or reactivation in bone, few attempts have been made to show similar effects histochemically. Bones from growing rats, when fixed in 4% buffered formaldehyde at room temperature and demineralized in 5% formic acid, exhibited expected inactivation of AcP. The inhibited AcP, however, was reactivated by pre-incubation of sections for 1 hr at 37°C in the following buffers: 0.2 M Tris, 0.2 M glycine, 0.2 M NaHCO3, or 0.1 M borax, as well as in alkaline water, but not in 0.2 M Na2HPO4 (all at pH 9). The reactivation was (a) site-specific (e.g., osteoclasts, osteoblasts, osteocytes, and cement lines), (b) temperature- and pH-dependent, (c) unaffected by OH- or SH--binding agents or by an alkaline phosphatase inhibitor, and (d) inhibited completely by 10mM Na2HPO4. The reactivation process, much simplified and/or more effective than with the methods previously reported, was observed in all 83 human biopsy bones embedded in methyl methacrylate and in human bones stored in cold buffered formaldehyde for 7 monts. This study demonstrates a unique method for reactivating and thus localizing the inhibited AcP in bones, and suggests possible applications in bone histomorphometry.

Original languageEnglish (US)
Pages (from-to)1355-1363
Number of pages9
JournalJournal of Histochemistry and Cytochemistry
Issue number12
StatePublished - 1987
Externally publishedYes

ASJC Scopus subject areas

  • Anatomy
  • Histology


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