Doxycycline counteracts bone morphogenic protein 2-induced osteogenic mediators.
BACKGROUND
Microbial colonization during wound healing may exaggerate the inflammatory response and could adversely affect the outcome of periodontal regeneration. Bone morphogenic proteins (BMPs) directly augment bone regeneration. Interestingly, inhibitors of tissue collagenases, such as sub-antimicrobial-dose doxycycline, also indirectly promote hard-tissue regeneration. In this study, it is hypothesized that BMP2-mediated bone regeneration would be positively affected by simultaneous treatment of sub-antimicrobial-dose doxycycline.


METHODS
Human periodontal ligament (PDL) cells were stimulated with: 1) 10 ng/mL BMP2; 2) 1 μg/mL doxycycline; or 3) a combination of the two. The expressions of alkaline phosphatase, osteocalcin, osteonectin, and osteopontin were analyzed along with in vitro mineralized nodule formation and calcium accumulation.


RESULTS
BMP2 was a potent inducer of osteocalcin/osteopontin (statistically significant at P <0.01) and osteonectin in PDL cells relative to stimulation with doxycycline. However, doxycycline relative to BMP2 (statistically significant at P <0.001) upregulated the expression of alkaline phosphatase and in vitro mineralized nodule formation. Contrary to expected results, combined BMP2 and doxycycline induced a statistically significant (P <0.001) downregulation of alkaline phosphatase, osteocalcin, osteonectin/osteopontin, and in vitro mineralized nodule formation compared to stimulation with either BMP2 or doxycycline alone.


CONCLUSIONS
Combined treatment of BMP2 and doxycycline in PDL cells counteracts the osteogenic mediators. Molecular interaction of growth factors should be explored before using a combination of these biologic molecules. It is important and clinically relevant to determine whether tetracycline and its other derivatives also counteract BMP functions. Animal models should be used to confirm these in vitro results.
Department of Periodontics, University of Washington, Seattle, WA, USA. manojm@u.washington.edu
Manoj
M
Muthukuru
Jeffrey
J
Sun
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D055396:Bone Morphogenetic Protein 2 / Q000037:antagonists & inhibitors / Q000502:physiology*; D001861:Bone Regeneration / Q000187:drug effects*; D002113:Calcification, Physiologic / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation; D004318:Doxycycline / Q000494:pharmacology*; D004347:Drug Interactions; D006801:Humans; D015675:Osteocalcin / Q000096:biosynthesis; D010012:Osteogenesis / Q000187:drug effects*; D015676:Osteonectin / Q000096:biosynthesis; D053495:Osteopontin / Q000096:biosynthesis; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism*; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors
D000900:Anti-Bacterial Agents; D055396:Bone Morphogenetic Protein 2; D015676:Osteonectin; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D015675:Osteocalcin; D053495:Osteopontin; D000469:Alkaline Phosphatase; D004318:Doxycycline