Experimental Study On Bone Sustitute β-TCP/PDLLA And β-TCP/rhBMP-2

Objective: To study the most suitable scale of P -TCP to PDLLA in the new porous bone substitute material of P -TCP/PDLLA. To study the most suitable pore size of 3-D porous 20% P -TCPIPDLLA for bone regeneration. To study the biocompatibility and the bone regeneration ability of PDLLA, P -TCP/PDLLA, PDLLAIrhBMP-2, P -TCP/PDLLA/rhBMP-2 which pore size is 200-300um. Method: (1) 13 -TCP was added to PDLLA in different scale and a particulate-leaching method was developed to prepare PDLLA, 5% P -TCP/PDLLA, 20% P -TCP/PDLLA, 35% P -TCP/PDLLA. The pH value, molecular weight, weight and biomechanics were observed during the degradation in 12W In vitro. (2)The different pore size material of 20% P -TCP/PDLLA were prepared and then were planted into rabbits?bilateral radius bone. The samples were examined by gross, X-ray, histomorphology and the biomechanics in 2W, 4W, 8W, 12W. (3)The bone defect of rabbit was planted with PDLLA or P -TCP/PDLLA or PDLLAIrhBMP-2 or P -TCP/PDLLAIrhBMP-2. The samples were examined by gross, X-ray, histomorphology, and the biomechan.ics in 2W, 4W, 8W, 12W Result: (1) The pH value , molecular weight, weight and biomechanics were different among PDLLA, 5% P -TCP/PDLLA, 20% P -TCPIPDLLA, 35% P -TCP/PDLLA during the degradation in 12W in vitro. (2)The bone defect planted with the material of 20% P -TCP/PDLLAIrhBMP-2 which pore size is 75-200um or 200-300um or 350-4SOurn or 400-700um was healed in 12W. The highest biomechanical strength was the group planted with the material which pare size was 200-300um . The defect planted with pore size under 75um 20% P -TCP/PDLLA and control group were occupied by connective tissues. (3)the bone defect planted with PDLLA or P -TCP/PDLLA or PDLLAIrhBMP-2 or P -TCP/PDLLA/rhBMP-2 were repaired in 1 2W.The there point strength in 12W: 20% P -TCPIPDLLA]rhBMP-2> PDLLAIrhBMP-2>20% P -TCP/PDLLA> PDLLA. 20%. The bone cell differentiation of P -TCP/PDLLA/rhBMP-2 and PDLLA/rhBMP-2 keep ahead of 20% β-TCP/PDLLA and PDLLA. Conclusion:(1) the most suitable scale of β-TCP to PDLLA in the new porous bone substitute β-TCP/PDLLA is i: 4. (2) The structure of 3D porous is important for bone regeneration, the 3-D porous PDLLAI P CP with 200-300um pore size is most suitable for bone substitute. (3) 20% β-TCPIPDLLAIrhBMP-2 is a promising material for bone defect.