Primary Study Of Silk Fibroin/Hydroxyapatite Membrane Guided Bone Regeneration In Rabbit Radii Defects

Purpose:To study the bone regeneration guided by silk fibroin/hydroxyapatite (SF/HA) membrane in rabbit radii defects.Methods:After the SF membrane was prepared by degumming method, the SF/HA membrane was developed by alternate soaking method. The models of 10 mm segmental defects were established in both radii of 9 adult New Zealand white rabbits. 6 as experimental group, the left defect (Group SF) was bridged with SF membrane tube, the right defect (Group SF/HA) was bridged with SF/HA membrane tube. The other 3 as controlled group, both defects (Group Blank) were untreated. General condition of the rabbits, such as the diet, activity and wound healing were observed postoperatively. To observe the healing status of bone defects, X-ray examination was performed at 2,4,8 and 12 weeks postoperatively. Otherwise, computer tomography (CT) 3D reconstruction was performed and cross-sectional images of bone defects were acquired to observe the healing status of bone defects 4,8 and 12 weeks postoperatively. The trend of guided bone regeneration in every group was evaluated according to the results above.Results:General condition:General conditions of all rabbits were good, no unusual activity, abnormal eating or signs of infection were observed postoperatively. X-ray examination:Rabbit radii defects were established in all groups at 2 weeks postoperatively. At 4 weeks postoperatively, a small amount of callus growth was observed in Group SF, and the bone regeneration of distal end is better than the proximal. No obvious callus growth in Group SF/HA, and a small amount of callus growth in Group Blank, the distal better than the proximal. At 8 weeks, significant callus growth was observed in Group SF, and the volume increased than that at 4 weeks, the distal end is still better than the proximal. No obvious callus growth in Group SF/HA, and callus growth near the ulna in Group Blank. At 12 weeks, more growth callus could be observed in Group SF, and the distal is similar to the proximal. Both ends were almost connected, so the area of bone defect was significantly reduced. A small amount of callus growth in Group SF/HA, and residual large bone defect area existed between the proximal end and the distal. Otherwise, callus growth near the ulna in Group Blank, residual bone defect area was also large. And the results of X-ray were supported by the cross-sectional images of bone defects acquired by CT 3D reconstruction. The percentages of guided bone regeneration trend were 66.67%(4 of 6) in Group SF,33.33%(2 of 6) in Group SF/HA and 0.00%(0 of 6) in Group Blank.Conclusion:The bone regeneration could probably be guided by SF membrane, while couldn't by SF/HA membrane in rabbit radii defects. Further improvements of SF-based membrane material is required to enhance its capacity in guided bone regeneration.