The Biological Effects Of Adenoassociated Virus-Mediated HTGF-β1 And HVEGF Encoding Genes Transfer On The Goat Degenerative Intervertebral Discs

Objectives: We establish a model of intervertebral disc degeneration in goat, and then transfect not only hTGF-β1 mediating by adeno-associated virus but also hVEGF encoding genes to the intervertebral disc degeneration in goat. At last we observe the expression of AAV-hTGF-β1 and hVEGF as well as the biological effects of monogenic transfection and digenic transfection on the degenerative intervertebral disc.Methods: We establish a model of intervertebral disc degeneration in SPF wethers adult goats by using the operating knife blade of number 11 to impair the left anterolateral annulus. We observe the changs of intervertebral disc by radiographic and histologic analyses in 4 weeks, 8 weeks, 12 weeks, 24 weeks after establishing models of intervertebral disc degeneration.successfully. Goats of intervertebral disc degeneration were divided into five groups in random, and the groups were A, B, C, D and E. The intervertebral discs of group A, B, C, D and E were injected rAAV2-hTGFβ₁, rAAV2- hVEGF, rAAV2-hTGFβ1 +rAAV2-hVEGF PBS, and rAAV2-EGFP respectively by the same volume of 50μL. analyses of Radiology, histologic and biochemistry were performed 2 weeks, 4 weeks, 8 weeks, and 12 weeks after the injection.Results: (1) Intervertebral disc slowly progressive degeneration was observed by radiology and histologic analyses. (2)The changs of discs transfection with therapy gene:â‘ Radiology analyses: The mean percent DHI of group A and C was significantly higher than in the D group (p＜0.05), which has statistical difference, and the result of group C was more significant than group A. There was no statistical difference in percent DHI between the group B and D.â‘¡Histologic analyses: We obtained the results of HE and Safranin-O stainning as follows: the loss of nucleus pulposus cells, the disorganized collagenous network and the loss of clear demarcation between the nucleus pulposus and inner annulus of group A and C were slighter than than that of group D, which has statistical difference, and the result of group C was more significant than group A; there was no statistical difference between group B and group D. The result of immunohistochemistry was as follows: The degree of the loss of strong positive stain ofâ…¡collagen within NP andâ… collagen within AF of group A and C were slighter than that of group D, which has statistical difference, and the result of group C was more significant than group A; there was no statistical difference between group B and group D. The content of rAAV2-hTGFβ1, rAAV2-hVEGF and rAAV2-hTGFβ1+rAAV2 -hVEGF in Group A, B and C was respectively more than that of group D. We can observed the expression of EGFP in group E transfected 12weeks later.â‘¢The biochemical result was as follows: The expression of collagenâ… ,â…¡and proteoglycan in group A and C was significantly more than that of group D (p＜0.05), and The result of group C more obvious than that in groupA, the difference has statistic significance (p＜0.05); There was no statistical difference in the group B and D. Conclusion: (1) The model appears ideal for the study of slowly progressive intervertebral disc degeneration.(2) The expression of rAAV2-hTGFβ1 and rAAV2 -hVEGFF can last 12 weeks after being transfected into degenerative discs.(3) The tansfection of hTGFβ1 can reverse the disc degeneration in a degree. (4) hVEGF can cooperate with TGFβ1 to reverse the disc degeneration.(5) cotransfection of hTGFβ1 and hVEGF has synergism.