The Study About Transplantation Of Bone Mesenchyal Stem Cells Recombined With Adenovirus Co-expression Vector Carrying The Human Transforming Growth Factor-beta1and Vascular Endothelial Growth Factor Genes To Improve Tendon-bone Healing After Cruciate Lig

Objective:The study about after cruciate ligament reconstruction whether transplantation of bone mesenchyal stem cells recombined with adenovirus co-expression vector carrying the human transforming growth factor-betal and vascular endothelial growth factor genes could improve the new bone formation,tendon-bone healing and biomechanics strength.Methods:The BMSCs of rabbits were harvested by bone marrow aspiration. BMSCs were isolated from bone marrow and purifed by density centrifuge and adhered to the cultural plastic in vitro. Standard Animal model of anterior cruciate ligament(ACL) reconstruction using ipsilateral semi-tendinosus tendon autograft in40mature New Zealand white rabbits were established and classified into2groups according to if transplantation of BMSCs recombined with adenovirus co-expression vector carrying the human transforming growth factor-betal and vascular endothelial growth factor genes(TGF-β1/VEGF165).There were20mature New Zealand white rabbits in each group. The experimental group was planted into by the composite of BMSCs recombined with adenovirus co-expression vector carrying the TGF-β1/VEGF165and fibrin glue while the control group was only planted into by the composite of BMSCs and fibrin glue. Ten rabbits each group were killed6,12weeks after operation.4of them were collected for histological observation of the tendon-bone healing using the coloration of HE and Sirius red.6of them were using biomechanical testing, recording the tensile force and stiffness as the bone-graft-bone complex breaking.The CT scan were performed to4rabbits each group12weeks after the operation to study the changes of the tunnel size and the bone mineral density.Results:In histological evaluation, the interface between tendon and bone of the experiment group at6weeks after the operation had relatively compactly integrated. Fibroblast, newly formed vessels and Sharpey’s fibre could be found in it, but the countral group of the interface did not heal very much,we could find fibroblast, mesenchymals and inflammatory cell.There was no newly formed vessels. The interface between tendon and bone of the experiment group at12weeks after the operation had very compactly integrated, a great quantity of cartilage cells and some newly formed vessels can be found in it, some skeltogenous cells can be found at the area of bone tunnel.A mature zone of cartilage was seen gradually blending from bone into the tendon grafts. But the control group of the interface there were a lots of fibroblast and Sharpey’s fibre. In biomechanical testing, all samples in the control and the experiment group at6weeks pulled out from the tunnel.At12weeks, only two samples in the control group was pulled from the tunnel and the remaining samples in the two groups were all broken in the central region of the tendon. Results of the experiment group and the control group at6and12weeks after the operation were be contrasted by matched t-test, the results was significant difference in statistics(P<0.05). CT examination at12weeks after the operation showed the size of the tunnel was not been extended in the experiment group and the control group.And the bone mineral density of the tunnel in the experiment group was greater than the control group.Conclusions:After cruciate ligament reconstruction,transplantation of bone mesenchyal stem cells recombined with adenovirus co-expression vector carrying the TGF-β1/VEGF165could increase the number of newly formed vessels and improve the new bone formation.So it could make tendon bone healing to the direction of direct healing.And then it could promote biomechanical characteristics.