The Use of Sequential VEGF- and BMP2-Releasing Biodegradable Scaffolds in Rabbit Mandibular Defects

PURPOSE

Promising developments have materialized in reconstructive surgical procedures with the applications of tissue engineering. In our study, we used tissue scaffolds fabricated from polylactic acid-polyethylene glycol (PLLA-PEG) copolymers to ensure different release rates of selective growth factors recombinant human bone morphogenetic protein 2 [rhBMP-2] and vascular endothelial growth factor (rhVEGF165) in the repair of mandibular bone defects.

MATERIALS AND METHODS

In our experimental study, 54 New Zealand rabbits were used. The rabbits were separated into 4 groups: group I (control group), PLLA-PEG scaffold only; group II, PLLA-PEG scaffold plus rhBMP-2 application; group III, PLLA-PEG scaffold plus VEGF165 application; and group IV, PLLA-PEG scaffold plus rhBMP-2 and VEGF165 applications. The rabbits were killed at 4 and 8 weeks postoperatively, and histopathologic and immunohistochemical assessments were performed.

RESULTS

The greatest bone volume was observed in rhBMP-2-containing groups, the greatest vessel volume was observed in VEGF165-containing groups; however, the scaffold containing rhBMP-2 and VEGF165 provided the best outcomes in conjunction with increased remodeling of the new bone.

CONCLUSIONS

The use of polymer tissue scaffolds that release rhVEGF165 and rhBMP-2 in coordination and mimic the natural healing process in the regeneration of especially complex tissues, such as bone, is a promising treatment alternative in the field of reconstructive surgery.

Effects of high fat diet induced obesity on peripheral nerve regeneration and levels of GAP 43 and TGF-β in rats

The increasing frequency of obesity is important because of its accompanying related health problems. The effects of obesity on peripheral nerves have not been elucidated. We investigated the effects of obesity on sciatic nerve regeneration using electrophysiology, stereology, immunohistochemistry, histopathology and functional tests. We used control, obese, control injured and obese injured groups of rats. Electrophysiological results showed that nerve conduction velocity and EMG were same in the experimental groups, but the amplitude of the compound action potential of the control group was significantly higher than that of the obese group. Examination of the nerves showed that the control and obese groups had both larger axon diameters and thicker myelin sheaths. The number of myelinated axons was decreased in both of the injured groups. Axon diameters and myelin sheath thicknesses of the control injured group were significantly greater those of the obese injured group. There were no significant differences in functional tests among the groups. Although growth associated protein 43 immunostaining in the control injured group was significantly greater than that of the obese injured group, no significant difference was observed between the control and obese groups. There was no significant difference in immunohistochemical staining for transforming growth factor beta 3 between the control injured and obese injured groups. Our results suggest that obesity may affect peripheral nerve regeneration negatively after crush injury.