The BMPs expression and histomorphometric study of beta-TCP /rhBMP-2 Grafting on the rabbit cranial bone defects

OBJECTIVE: The Purpose of the study was to investigate the bone morphogenic protein expression of rhBMP-2(recombinant human bone morphogenic protein-2) as singnaling molecule and beta-TCP(Tricalcium phosphate) as a bone substitute and carrier medium of rhBMP-2. MATERIALS AND METHODS: 16 rabbits divided into 2 group of each 8 rabbit. Two standardized bone defect, round bilateral defect was made in the cranium of the 8 rabbit of first group, and was grafted with 150~500micrometer diameter beta-TCP 0.25g in one side, which was soaked with rhBMP-2, and autogenous bone was grafted on another side as a positive control. Second group of 8 rabbit, only beta-TCP was grafted with same size and same manner. After 2, 4, 8, and 12 weeks, specimen was taken for microscopic immunohiostochemical and histomorphometric analysis. RESULT: Grafting beta-TCP with rhBMP show the early formation of the bone regenerative factor (BMP-4) and more quantity of new bone formation than only use of beta-TCP (8,12 week), even show less new bone formation than autogenous bone. CONCLUSION: The experimental study result that beta-TCP graft combination with rhBMP-2 as a delivery system is an effective with osteoinductive capacity and biodegradable properties, so that provide clinical availibility of composite use in reconstruction of bony defect.

The effect of pulsed electromagnetic fields on beta-TCP graft in rabbit cranial bone defect

The purpose of this research was to investigate whether pulsed electromagnetic field (PEMF) stimulation applied to the rabbit cranial defects grafted with beta-tricalcium phosphate (beta-TCP) could affect the new bone formation. With 16 New Zealand white rabbits under the same condition, bilateral calvarial bone defects were formed around the sagittal suture line. The defect on the left side was grafted with beta-TCP, while on the right side was grafted by harvested autogenous bone. PEMF was applied to 8 rabbits for 8 hours per day. The bony specimen were divided into 3 groups, the group 1 was autogenous bone grafted specimen, the group 2 was beta-TCP grafted with PEMF, and the group 3 was beta-TCP grafted without PEMF. We investigated the bone regeneration and growth factor expression at 2, 4, 6, and 8 weeks. As a result, BMP 2 was expressed in the group 1 from 2 weeks, the group 2 from 4 weeks, and the group 3 from 6 weeks. BMP 4 was expressed in the group 1 from 2 weeks, in the group 2 and the group 3 from 4 weeks. 4. There was no significant difference in expression pattern of BMP 7, PDGF, VEGF, and TGF-beta1 during grafted bone regeneration in group 1, 2, and 3. According to our results, PEMF stimulation could be effective on the new bome formation in animal study, and have a feasibility of clinical use.

The effect of prp on the bone regeneration of beta-tcp grafted in rabbit cranial bone defect