Recombinant human bone morphogenetic protein-2/atelocollagen composite as a new material for ossicular reconstruction

Ossicular reconstruction is the rebuilding of the damaged middle ear. There are many different prosthesis and techniques used to reconstruct the middle ear ossicles. However, precision in the surgical procedures and prostheses used for ossiculoplasty are still imperfect. The objective of this study was to evaluate the potential of recombinant human bone morphogenetic protein-2 (rhBMP-2)/ atelocollagen composite for ossicular reconstruction implanted in the tympanic cavity of rat. The ossicles were extirpated by perforating the tympanic membranes of rats. rhBMP-2/atelocollagen composite was implanted as substitute of ossicles in intimate contact with the tympanic membrane. Composites were subjected to histological, immunohistochemical, and radiological examination. To evaluate the auditory function, auditory brainstem response (ABR) was measured. rhBMP-2/atelocollagen composites showed good stability and durability without any inflammatory reaction within the tympanic cavity. The process of new bone formation was similar to intramembranous ossification. They also demonstrated that the hearing ability was re-established by ABR threshold shifts. rhBMP-2/atelocollagen composite exhibited excellent potential for ossicular reconstruction, maintaining their vibratory function. This ossicular tissue engineering may be considered as a future therapeutic strategy for ossiculoplasty.