Several different bioabsorbable scaffolds designed and manufactured for guided bone regeneration and generation have been developed and intensively studied. However, little information is available concerning the enzymes involved in their absorption. Objective: The aim of this study was to evaluate the specific activity of acid (tartrate resistant and lisosomal acid phosphatase) and alkaline phosphatase, protein tyrosine phosphatases, arilsulfatase, and b-hexosaminidase, in response to implant of demineralized membrane derived from bovine bone with or without adsorbed tetracycline. Methods: After 1, 3, 7, 15, 30 and 60 days post implantation 60 rats (Rattus novergicus, 70 days-old) were sacrificed. The reaction tissue collected was homogenized in 0.1M acetate buffer (1:10 w:v), pH 5. After centrifugation supernatant was used to assay acid phosphatases, arilsulfatase and b-hexosaminidase. Precipitate was dissolved in tris-HCl buffer 0.1M, pH 7.5 (plus 0.2% Triton X-100, 2mM MgCl2 and 150 mM NaCl) and after centrifugation the supernatant was used to assay alkaline phosphatase. As substrate, acid phosphatases activities were determined using 5mM p-nitrophenylphosphate (pNPP, pH 5), alkaline phosphatase activity using 1 mM pNPP (pH 9,4), arilsulfatase assay used 5mM p-nitrocatecol-sulfate (pH 5) and b-hexosaminidase activities was determined using 3 mM p-nitrophenil-N-acetil-b-D-glucosaminide (pH 4.5). Results: Acid phosphatase, PTP and b-hexosaminidase specific activities increased after membranes implantation reaching the maximum value at 7th day. TRAP specific activity was extremely low in all groups (less than 2 nmol mg-1 min-1). Lisosomal acid phosphatase activity at first and 60th was not statistically different. Arilsulfatase and alkaline phosphatase showed maximal activity at the first and 3rd days but significantly decreased until the 60th day. Tetracycline induced the highest specific activity at days 1 and 3 for all enzymes tested. Conclusion: Lisosomal enzyme markers (FAL, arilsulfatase and b-hexosaminidase) were more active during the first 3 days post-implantation while TRAP activity was very low.

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