Effect of pcDNA3.1-VEGF165 recombined vector on bone defects / 中华骨科杂志

ABSTRACT

Objective To construct the vector pcDNA3.1 containing VEGF165 gene and examine of pcDNA3.1-VEGF165 vector to the angiopoiesis, composition of collagen in rabbit bone defect model. Methods Extract total RNA from the rabbit tissue. Prepare cDNA by inverse transcription and clone the gene by PCR. Clone plasmid pMD18-T/VEGF165 combined with pcDNA3.1 to reconstruct pcDNA3.1- VEGF165. 28 New Zealand white rabbits weighted (2.0?0.130) kg were made bone defect model for 10 mm length in the bilateral radii. Cut down the skin, resect the bone of 10 mm in length in the middle of radius. The pcDNA3.1-VEGF165 0.2 ml (200 ng) plasmid was injected at one defect side randomly. The defect in the other side was served as control group, and injected with absorbable gelatin sponge and sodium chloride 0.2 ml. After the examination by X-ray the local specimens were obtained at 1,2,4,6,8,and 12 weeks respectively. The expression of collagen type Ⅰ and Ⅲ was examined at 4, 12 weeks by immunohistochemical staining techniques. Results The pcDNA3.1-VEGF165 vector was constructed successfully. The roentgenography: there was no difference between the two sides after 1 week operation; 2 weeks after the operation, there were some callus in the experimental group; there was nothing in the control group. After 4 weeks, there were much callus, synostosis and others in the experimental group, all of these were late in the control group. Two groups were healed after 12 weeks, the bone density was lower in the control group. Inflammatory cell infiltrate, cellular interstitialis, fibroblast, collagen and osteoblast were no difference between the two groups only at the first week, but the density of angiogenesis was much more in the experimental group at the following times. Expression of collagen type Ⅰ, Ⅲ were more intensity in the experimental group than the control one at 4,12 weeks. Conclusion Transcription to local bone cells at defect position with pcDNA3.1-VEGF165 plasmid can enhance quantity of the angiopoiesis, extra cellular matrix and the healing of bone defect.