The effects of storage conditions on the preservation of enzymatic activity in bone

Alkaline phosphatase and acid phosphatase are two major enzymatic measures of osteoblastic and osteoclastic activity, respectively. As a result, the preservation of the enzymes in bone specimens to near in vivo accuracy is essential. Despite standardization of the staining process, several factors related to the storage of blocks and slides before sectioning and staining impact the level of enzymes detected in the tissue. Block condition (intact, faced, or unstained) as well as environment (temperature and length of time in storage) affect alkaline phosphatase preservation while the acid phosphatase enzyme remains unaffected. We conclude that to optimally preserve alkaline phosphatase enzyme, methacrylate-embedded undecalcified murine bones should be stored as intact blocks. After sectioning, the faced blocks should be stored at 4°C for optimal enzyme staining of future sections. Furthermore, it is best to stain sections immediately after sectioning.