| Objective:To study the effect of local application of autologous bone mesenchymal stem cells (bMSC) and VEGF165 on tendon-bone healing after acute injury and repair of suprospinatus tendon.Methods:The bMSC of rabbits were harvested by bone marrow aspiration. BMSC were isolated from bone marrow and purified by density centrifuge and adhered to the cultural plastic in vitro. We randomly divided sixty New Zealand white rabbits into three groups-Control group, VEGF group and MSC group. We exposed the bilateral suprospinatus tendon and abscised the eight millimeter length tendon inserstion of the middle part. We made two bone tunnel on the greater tubercle of the humerus and sutured the abscised tendon on the greater tubercle. We injected 0.1ml FG to each side on Control group,0.1ml FG+1X106 bMSC on MSC group and 0. 1ml FG+100ng VEGF on VEGF group. The rabbits were harvested at 4,8,12 weeks postoperatively for histological study.Results:The healing rate of MSC group and VEGF group were 89.5% and 90.6% respectively. It was significantly higer than Control group (P<0.05). Control group showed mature scar tissue with some fibers spanning the tendon-bone interface at 8 weeks. The fibrocartilage transition zone appeared at 12 weeks. In the MSC-enhanced group, granulation tissues connected the tendon and the bone. There were some cartilage-like cells at the tendon-bone junction at 4 weeks. By 8 weeks, a mature zone of cartilage was seen gradually blending from bone into the tendon grafts. At 12 weeks there appeared tide mark and the tendon-bone insertion appeared like the normal tendon-bone insertion.The tendon-bone maturing score of MSC group were significantly higher than that of Control group(P<0.05). In VEGF group, collagen fibres connected the tendon and bone and there were some new-born vessels at 4 weeks. At 8 weeks, there were some cartilage-like cells and the vessels decreased. The tendon-to-bone connected tightly at 12 weeks and there were more collagen fibres. Some fibres anchored in the bone and there were some fibrocartilage cells between fibres. But there was no tide mark. The tendon-bone maturing score of VEGF group were significantly higher than Control group at 4 and 8 weeks(P＜0.05), and there was no difference at 12 weeks (P＞0.05).Conclusions:Tendon-bone interface transplanting bMSC and VEGF results in healing by an intervening zone of cartilage resembling the chondral enthesis of normal tendon insertions rather than collagenfibers and scar tissue. VEGF can promote new-born vessels formation in the early period of tendon-bone healing.
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