| Objective:To investigate the effect of stromal vascular fraction(SVF)from autologous adipose on rotator cuff healing in rabbits and provide experimental basis for clinical promotion of rotator cuff tendon healing.Methods:35New Zealand rabbits of similar weight were randomly selected and divided into three groups.In the control group,the model of acute rotator cuff tear was established.In the experimental group,SVF was injected around the tendon bone interface after the acute rotator cuff tear model was established,and SVF was injected around the supraspinatus muscle insertion after surgical suture of the rotator cuff,and the wound was closed layer by layer.In the blank group,New Zealand rabbits died directly on the shoulder band after feeding for 12 weeks.The control group and the experimental group were divided into groups at 4,8 and 12 weeks for gross specimen observation,biomechanical test and histological observation.Results:1.Gross specimen observation: 4 weeks after surgery: tendon healing was not observed in the two groups,and there were different degrees of adhesion and scar tissue.8 weeks after surgery: the gap was still visible in the tendine-bone joint of the control group,the supraspinatus tendon healed well in the experimental group,the supraspinatus tendon was effectively attached to the greater tuberosity of the humerus,and the gap between the tendinous bones was not obvious.12 weeks after surgery: a small amount of scar tissue was still visible in the control group,the tendon healed well,and the tendine-bone gap was dimly visible,which was significantly reduced compared with 4 or 8 weeks,In the experimental group,the rotator cuff healed well,the tendine-bone gap disappeared,and there was no obvious scar tissue around the supracaspinatus tendon,similar to a blank group.2.Biomechanical results: The maximum tensile load measured by biomechanics in both the control group and the experimental group increased gradually with the extension of postoperative time.4 weeks after surgery: there was no significant difference in the maximum tensile load between the experimental group and the control group,and there was no statistical difference in the biomechanical test results between the two groups(P > 0.05).8 weeks after surgery: there was no statistical difference in the maximum tensile load between the control group and the experimental group(P > 0.05).12 weeks after surgery: the tensile strength of the experimental group was significantly stronger than that of the control group,and the maximum tensile load of the tendine-bone interface of the experimental group was significantly greater than that of the control group,and the difference between the two was significant(P<0.05).Compared with the blank group,the maximum tensile load of the control group and the experimental group was lower than that of the blank group 12 weeks after surgery,and the difference between the control group and the blank group was more significant,with statistical difference(P<0.05).3.Histological observation: 4 weeks after operation: there was no tendon bone healing in the control group and the experimental group,and there were different degrees of neovascularization and inflammatory cells.Meanwhile,a small number of fibroblasts were observed in the experimental group,and no collagen fiber formation was observed.8 weeks after surgery:both groups showed a certain degree of healing tendency.In the experimental group,some fibrous cartilage and collagen fibers were seen in the sections,and the fibrous cartilage was gradually extended to the tendon.12 weeks after surgery: tendon healing was effective in both groups.Sections of the control group showed a large number of chondrocytes distributed at the tendine-bone junction,a small number of fibrochondrocytes,and some of them differentiated towards osteoblasts,the tendinous bones are connected by collagen fibers and arranged in regular order.In the experimental group,the tendine-bone bond was tight,the collagen fiber bundles were arranged regularly in the tendine-bone gap,and they grew into the tendon,similar to the normal tendon stop structure.Conclusion: Using SVF can shorten the healing time of rabbit rotator cuff repair tendon and bone,promote the reconstruction of tendon and bone interface stop point,and thus promote rabbit rotator cuff repair. |
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