Objective To investigate the effect of rhBMP-2 combined with porous CPC on spine fusion in rabbits. Methods rhBMP-2 (1 mg) was loaded with 1 g CPC and 6.0 cm × 2.0 cm × 0.5 cm absorbable gelatin sponge (AGS), respectively, and thereafter frozen to prepare the biomaterial of rhBMP-2/CPC and rhBMP-2/AGS. Forty-five 24-week-old New Zealand rabbits (weight 2.5-3.5 kg) were randomly divided into 3 groups: group A (n=17), group B (n=11) and group C (n=17).With the exposure and removal of L5, 6 transverse process’s posterior bone cortex in all the rabbits, the corresponding cancellous bones were exposed and the posterior bilateral intertransverse bone grafting of L5, 6 were performed on the three groups, then the rhBMP-2/CPC, rhBMP-2/AGS and CPC was implanted into the rabbits of group A, B and C, respectively. Gross observation, histology assay and image examination were conducted 4, 8 and 24 weeks after operation. Results Decalcified hard tissue section demonstrated obvious callus connections in group A, small pieces of callus in group B, and fibrous connection and few cartilage in group C at 4 and 8 weeks after operation. By Kacena measurement standard, the score of group A, B and C at 4 weeks after operation was (7.30 ± 0.76), (3.68 ± 1.60) and (1.75 ± 0.54) points, respectively, and their score at 8 weeks after operation were (8.32 ± 1.11), (3.75 ± 1.23) and (1.47 ± 0.23) points, respectively, indicating there were significant differences between group A and group B as well as between group A and group C at different time points (P lt; 0.05). Undecalcified hard tissue section demonstrated that there was cancellous bone-l ike tissue regeneration in group A, and fiber connection around the implants and l ittle ossification in group C at 4 and 8 weeks after operation. By three dimensions reconstructed CT, group A, B and C scored (2.50 ± 0.57), (1.00 ± 0.00) and (1.00 ± 0.00) points respectively, indicating there was a significant difference between group C and groups A and B as well as between group A and group B (P lt; 0.05). Conclusion As a carrier of rhBMP-2, the CPC is capable of promoting spine bone fusion in rabbits and is a new type of artificial bone repair material.
To investigate the cl inical results and the mechanism of bone heal ing for the repair of bone defects following tumor resection with novel interporous TCP bone graft, and to test the hypothesis of “structural transplantation”. Methods From January 2003 to December 2005, 61 cases of various bone defects following the curettage of the benign bone tumors were treated with interporous TCP, with 33 males and 28 females, including bone fibrous dysplasiain 8 cases, bone cyst in 23 cases, eosinophil ic granuloma in 12 cases, enchondroma in 13 cases, non-ossifying fibroma in 2 cases, and osteoblastoma in 3 cases. Tumor sizes varied from 1.5 cm × 1.0 cm to 7.0 cm × 5.0 cm. The plain X-ray, single photon emission computed tomography (SPECT) and histology examination were obtained at various time points after operation. The in vivo biodegradation rate of the implanted TCP was evaluated based on a semi-quantitive radiographic analyzing method. Histopathology examination was performed in 1 revision case. Results All the patients were followed up for 5 to 24 months after operation. They all had good wound heal ing and bone regeneration. There was neither significant reverse reaction to the transplanted material nor locally inflammatory reaction in all of the cases. The bone defects were repaired gradually from 1 to 6 months after operation (bone heal ing at average 2.6 months after surgery) with a bone heal ing rate up to 96.7%. There was only 1 recurrence case (eosinophil ic granuloma in ischium) 3 months after operation. Given revision operation, this case gained bone heal ing. Radiographically, the interface between the implanted bone and host bone became fuzzy 1 month after implantation, indicating the beginning of new bone formation. Three months later, the absorption of the interporous TCP was noticed from peripheral to the center of the implanted bone evidenced by the vague or fuzzy realm. New bone formation could be seen both in peri pheral and central areas. Six months later, implanted bone and host bone merged together and the bone defect was totally repaired, with 78.9% degradation rate of the implanted TCP. Twelve months later, the majority of the implanted bone was absorbed and bone remodel ing was establ ished. In the cases that were followed up for 24 months, the function of affectedextremity was excellent with good bone remodel ing without recurrence. In 2 cases, SPECT showed that nucl ide uptake could be observed in implanted site and the metabol ic activity was high both in the central as well as the peripheral areas of the graft 1 month after implantation, which was an evidence of osteogenesis. Pathologically, the interporous TCP closely contacted the host bone inside the humerus 1 month after grafting. The interface between the implanted bone and host bone became fuzzy, and vascularized tissue began growing inside the implanted graft as a “l ining” structure. Conclusion The interporous TCP proves to be effective for cl inical reparation of bone defects following tumor resection. The inside three-dimensional porous structure simulates the natural bionic bone structure which is suitable for recruitment related cells in-growth into the scaffold, colonizing and prol iferation companied with the process of vascularize, finally with the new bone formation. The novel interporous TCP may boast both bone conductive and bone inductive activities, as an appeal ing “structural transplantation” bone graft.
Because of its high biological compatibility, titanium has been a good biomaterial. The implanted artificial bone made from titanium can contact with the vital and mature osseous tissue directly within 3-6 months, the so-called osteointergration. In order to promote the process of osteointergration, FDBM of rabbit was prepared and was combined with pure titanium so as to speed up osteointergration. The study focused on bone density, bone intergration rate, new bone growth rate around the pure titanium, and the Ca2+ and PO(4)3- density of titanium-bone interface. A control group of pure titanium inplant without FDBM was set up. The results showed FDBM had no antigenicity. It could induce and speed up the new bone formation at titanium-bone interface. The titanium-bone intergration time was within 2 months. It was suggested that there were more bone morphogenesis protein (BMP) or other bone induction and bone formation factors in brephobone than that in child and adult bone. As a kind of bone induction material, FDBM was easy prepared, cheap in price, easy to storage, no antigenicity and obvious bone-inductive function.