engleski

Biological repair of thyroid cartilage defects by osteogenic protein-1 (bone morphogenetic protein-7) in dog

The efficacy of human recombinant osteogenic protein-1 (OP-1 ; bone morphogenetic protein-7) in regeneration of dog larynx was examined by treating thyroid cartilage defects (1.5 cm2) in dogs with thyroid allografts covered with host perichondrium or fascia. Prior to implantation allografts were frozen, thawed and demineralized. The treatment groups were as follows: I/ Allograft control implant (n=3) ; II/ Implants coated with 500 mg OP-1 (n=4) ; III/ Implants coated with 100 mg OP-1 (n=3) ; IV/ Implants coated with 500 mg OP-1 and covered with neck fascia (n=3) ; and V/ Implants extracted with 1M NaCl and guanidine hydrochloride, and coated with 500 mg OP-1 (n=3). Dogs were killed four months following surgery. Each larynx was removed, carefully dissected and a three-dimensional reconstruction of the defect area was performed on serial sections. The results revealed that the implants of control dogs remained intact with no apparent reduction in size and new tissue formation. OP-1 enriched thyroid allografts, dose dependently induced bone, cartilage and ligament-like structures comprising up to 80% of the total regenerated defect area. Boundaries of the defects healed by formation of new bone when bone resided within the old thyroid cartilage layers. Boundary areas lacking bone inside cartilage layers healed by formation of cartilage, with excellent integration of new and old cartilage. Both new bone and cartilage were embedded into layers of new ligament-like tissue which expressed specific morphologic and molecular markers. The three newly formed tissues were tightly connected into a "bone-cartilage-ligament continuum" of tissues suggesting that OP-1 served as a multiple tissue morphogen in this specific microenvironment.

osteogenic protein -1; cartilage repair; new cartilage; bone and ligament like tissue

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