Enzyme histochemical studies of acid phosphatase isoenzymes in induced heterotopic bone formation in guinea pigs.

A bone induction model was used to study the effect of different pretreatments and inhibitors added to the substrate media used for the histochemical demonstration of acid phosphatase activity. Two different acid phosphatases (AcP) were demonstrated. The AcP of matrix-producing cells exhibited resistance to pretreatment with EDTA while it was sensitive to tartrate added to the incubation medium. The AcP in dentin resorbing cells was EDTA sensitive but resistant to tartrate. The AcP activities in both resorbing and matrix-producing cells generally sensitive to fluoride, copper and molybdate. In some of the dentinoclasts, fluoride resistant AcP was observed. The results suggest previous investigations on normal bone formation, suggesting that at least two different isoenzymes of AcP exist. One of these seemed to be related to matrix production and mineralization of the new heterotopic bone.