title: In vivo assessment of a multicomponent and nanostructural polymeric matrix as a delivery system for antimicrobials and bone morphogenetic protein-2 in a unicortical tibial defect in goats.
abstract: OBJECTIVE
  To determine the response of cortical bone to a multicomponent and nanostructural polymeric matrix as a drug delivery system for enhancing bone healing.
  
  
  METHODS
  20 healthy adult crossbred goats.
  
  
  METHODS
  A 3.5-mm-diameter unicortical defect was created in each tibia (day 0), and goats (4 goats/group) were treated as follows: not treated (control group), grafted with the matrix, grafted with antimicrobial (tigecycline and tobramycin)-impregnated matrix, grafted with recombinant human bone morphogenetic protein type 2 (rhBMP-2)-impregnated matrix, or grafted with antimicrobial- and rhBMP-2-impregnated matrix. Elution kinetics of antimicrobials was monitored through plasma concentrations. Bone response was assessed with radiographic scoring (days 1 and 30) and dual-energy x-ray absorptiometry (days 1, 14, and 30). Goats were euthanized on day 30, and histomorphologic analysis was performed. Categorical variables were analyzed with a generalized linear model, and continuous variables were analyzed with an ANOVA.
  
  
  RESULTS
  Plasma antimicrobial concentrations indicated continued release throughout the study. Radiography and dual-energy x-ray absorptiometry did not reveal significant differences among treatments on day 30. Periosteal reactions were significantly greater surrounding bone defects grafted with rhBMP-2-impregnated matrix than those not treated or grafted with matrix or with antimicrobial-impregnated matrix; periosteal reactions were similar in bone defects grafted with rhBMP-2-impregnated matrix and antimicrobial- and rhBMP-2-impregnated matrix.
  
  
  CONCLUSIONS
  The matrix served as an antimicrobial delivery system and stimulated bone proliferation when rhBMP-2 was present. Antimicrobial and rhBMP-2 can be used concurrently, but the presence of antimicrobials may affect the performance of rhBMP-2.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506.
authors.forename: Marjolaine
authors.initials: M
authors.lastname: Rousseau
authors.forename: David E
authors.initials: DE
authors.lastname: Anderson
authors.forename: James D
authors.initials: JD
authors.lastname: Lillich
authors.forename: Michael D
authors.initials: MD
authors.lastname: Apley
authors.forename: Peder J
authors.initials: PJ
authors.lastname: Jensen
authors.forename: Alexandru S
authors.initials: AS
authors.lastname: Biris
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage / Q000494:pharmacology*; D001862:Bone Resorption / Q000517:prevention & control; D016025:Bone Transplantation / Q000379:methods / Q000592:standards; D004343:Drug Implants; D005260:Female; D006041:Goats; D008911:Minocycline / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D049329:Nanostructures; D011108:Polymers; D011897:Random Allocation; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D013977:Tibia / Q000000981:diagnostic imaging / Q000293:injuries*; D000078304:Tigecycline; D014031:Tobramycin / Q000008:administration & dosage / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000494:pharmacology*; D014945:Wound Healing / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D055396:Bone Morphogenetic Protein 2; D004343:Drug Implants; D011108:Polymers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D000078304:Tigecycline; D008911:Minocycline; D014031:Tobramycin