Repair of segmental long bone defect in a rabbit radius nonunion model: comparison of cylindrical porous titanium and hydroxyapatite scaffolds.

A segmental long bone defect in a rabbit radius nonunion model was repaired using cylindrical porous titanium (Ti) and hydroxyapatite (HA) scaffolds. Each scaffold was produced using the same method, namely, a slurry foaming method. Repairing ability was characterized using x-radiographic score 12 and 24 weeks postprocedure; failure load of the radius-ulna construct, under three-point bending, 12 weeks postprocedure; and the percentage of newly formed bone within the implant, 12 and 24 weeks after postprocedure. For each of these parameters, the difference in the results when porous Ti scaffold was used compared with when HA scaffolds were used was not significant; both porous scaffolds showed excellent repairing ability. Because the trabecular bone is a porous tissue, the interconnected porous scaffolds have the advantages of natural bone, and vasculature can grow into the porous structure to accelerate the osteoconduction and osteointegration between the implant and bone. The porous Ti scaffold not only enhanced the bone repair process, similar to porous HA scaffolds, but also has superior biomechanical properties. The present results suggest that porous Ti scaffolds may have promise for use in the clinical setting.

Preparation of electrospun PLGA-silk fibroin nanofibers-based nerve conduits and evaluation in vivo.

With advances in technical methodology, the grafting of biocompatible conduits may become a viable alternative for the reconstruction of nerve gaps. In this study, electrospinning was used to fabricate nerve conduits (NCs) from poly(L-lactide-coglycolide)-silk fibroin. Conduits or autograft nerves were employed to bridge 10 mm defects in the sciatic nerves of Sprague-Dawley rats. Six weeks after the operation, morphological and functional assessment showed that nerve conduits from PLGA-silk fibroin grafts promoted the regeneration of peripheral nerves. The effects were similar to those obtained using nerve autografts. This method offers a promising alternative to the use of nerve autografts.

[Histological and biomechanical study of repairing rabbit radius segmental bone defect with porous titanium].

OBJECTIVE: To investigate the therapeutic effects of porous titanium (Ti) on the recovery of rabbit radial bone defect. METHODS: Bone defects were artificially made in 30 New Zealand rabbits by resecting the 1 cm substantial osseo with periosteum of both radii. The left anterior limbs were implanted with porous titanium, while the right anterior limbs with porous hydroxyapatite (HA). The rabbits were sacrificed at three time points. Both the radii healing statuses were observed by histology and histomorphometry analyses by means of computer graphic processing at the end of 8, 12 and 24 weeks, and biomechanical analyses at the end of 12 and 24 weeks. RESULTS: The histology examination showed that mass newly formed bone had grown into most pores of both the specimens. Along with prolongation of times after operation, the ingrowths of bone cells and effects of bone remodeling in the research side were nearly the same as those in the control side at the end of 12 and 24 weeks. The interface between the new bone and implants showed tight contact in both the groups without an obvious fibrous tissue. The results of histomorphometrical analyses showed that a statistically significant difference was not obtained for % bone area (bone area/ gross implant) between both the groups (P>0.05).However, the results of maximum failure load for the Ti group and the HA group were (107.34±27.44) N and (93.42±21.18) N at the end of 12 weeks, (118.56±24.65) N and (102.15±23.37) N at the end of 24 weeks, respectively. Biomechanical properties of the Ti group was stronger than that of the HA group, however, a statistically significant difference was not obtained between both the groups (P=0.102). CONCLUSION: Porous titanium scaffold can promote the formation of new bone, which contributes to the healing of long tubular bone defect. The porous titanium can enhance the bone repairing effect on segmental bone defect nearly the same as porous hydroxyapatite .

Experimental study on the adhesion, migration and three-dimensional growth of Schwann cells on absorbable biological materials.

OBJECTIVE: To study the adhesion, migration and three-dimentional growth of Schwann cells on PLA (polylactic acid) nonspinning fibre cloth and polyglycolic/polylactic acid (PLGA) fibres. METHODS: Schwann cells/ECM gel solution and PLA nonspinning fibre cloth and PLGA fibres pretreated by collagen, polylysine and ECM were co-cultured. Then the migration and three-dimensional growth of Schwann cells on the fibres were observed under phase contrast microscope and laser scanning confocal microscope. RESULTS: Schwann cell/ECM solution was compounded with PLA nonspinning fibre cloth. With formation of gel, most Schwann cells resided in the fibre net holes, and adhered to the fibres to form a multiplayer-arranged Schwann cell column like Büngner band. Schwann cells could adhere to PLGA fibres and grew and migrated along the fibres. ECM gel could significantly increase the adhering and migrating cell number. CONCLUSIONS: ECM gel can facilitate the adhesion, growth and migration of Schwann cells on the seteroframe. It is a good integrating material for tissue engineering bioartificial nerve.