| Objective: To investigate the mechanism of PRP combined with BMAC in the treatment of Achilles tendinopathy and provide theoretical basis for its clinical application.Methods: 45 New Zealand white rabbits were randomly divided into 6 groups: group A(PRP group),group B(BMAC group),group C(PRP + BMAC group),group D(treatment control group),group E(model group)and group F(blank control group).Among them,8 in group A,B,C and D,4 in Group E and F,and 5 in Group E were used for blood collection and bone marrow extraction to prepare PRP and BMAC.A.In group B,C,D and E,the Achilles tendinopathy model was induced by PGE2 injection.Four weeks later,muscle and bone ultrasound was used to observe the tendon morphology of all rabbits.Three rabbits in Group E and group F were randomly selected to test the content of collagen I,collagen III and IL-1 ?.After successful modeling,group a received PRP injection,group B received BMAC injection,group C received PRP + BMAC injection,and group D received the same amount of saline injection,once for each group.Four animals were killed by air embolism after 7 days and 14 days respectively,and the experimental indexes were observed in turn to compare the differences among the groups.(1)HE staining was used to observe the morphological structure of tendon;(2)QRT PCR was used to detect the expression of collagen I and collagen III mRNA in Achilles tendon;(3)WB method was used to detect the expression of IL-1 ? protein in Achilles tendon.Results: the animals in this group were generally in good condition without adverse events or accidental death.(1)Four weeks after the establishment of the model,the boundary of Achilles tendon in group A,B,C,D,E was unclear,thickened,echo decreased,obvious abnormal blood flow signal was seen,and the morphology of Achilles tendon in group F was normal,which indicated that the Achilles tendon disease animal model was successful.(2)HE staining: in group F,the fibers were arranged orderly,orderly and compact,without obvious wave shape,scattered in fusiform tendon cells,and the number of fibroblasts was very few,which was normal Achilles tendon histology;in groups D and E,the fibers were arranged disorderly,loose,seriously broken,wavy,and the fibroblasts were obviously increased,with obvious abnormal neovascularization;after 7 days of intervention,the Achilles tendon fibers in groups a,B and C were significantly increased The arrangement was still disordered,slightly broken and loose,with medium amount of fibroblasts distributed,and a small amount of neovascularization was found in groups A and B;after 14 days,there was no significant difference in the arrangement of fiber structure between groups A and B and 7 days,but the number of fibroblasts increased,no obvious neovascularization was found,and the fibers in group C were arranged orderly,without fracture,with a large number of fibroblasts distributed.In group D,the fiber arrangement was still disordered,moderately broken,loose,with medium amount of fibroblast distribution and obvious neovascularization.(3)Expression of type I and III collagen: after 4 weeks of PGE2 injection,the expression of type I and III collagen in Group E and F was(0.519 ± 0.086)(3.190 ± 0.728),(0.943 ± 0.133)(1.069 ± 0.432),respectively.Compared with group F,the expression of type I collagen m RNA decreased,and the expression of type III collagen mRNA increased in Group E,the difference was statistically significant(P < 0.05),indicating that the model was successful.After 7 days of intervention,the expression of type I and III collagen in group A,B,C and D was(1.400 ± 0.428)(6.468 ± 0.749),(1.417 ± 0.328)(5.590 ± 0.436),(2.179 ± 0.467)(10.894 ± 1.000),(0.547 ± 0.216)(3.707 ± 0.488),respectively,and the expression of type I and III collagen in group A,B and C was increased significantly in group C.There was no statistical difference between groups A and B except for the difference between groups A and B The difference between the other groups was statistically significant(P < 0.05).After 14 days,the expression of type I and III collagen in group A,B,C and D was(1.500 ± 0.324)(6.891 ± 0.537),(1.851 ± 0.316)(7.310 ± 0.794),(2.680 ± 0.429)(9.057 ± 1.116),(1.107 ± 0.315)(4.994 ± 0.592),respectively.The expression of type I collagen in group C was significantly higher than that in group A,B and D(P < 0.05).The difference was statistically significant(P < 0.05)The content of collagen in group A,B and D increased,while that in group C decreased,but it was still higher than that in group A,B and D(P < 0.05).(4)Expression of IL-1 ? protein content: after 4 weeks of PGE2 injection,the expression of IL-1 ? protein content in E and f groups were(1.000 ± 0.173)and(0.279 ± 0.019),respectively.The difference between the two groups was statistically significant(P < 0.05),indicating that PGE2 can induce inflammation of Achilles tendon.The expression of IL-1 ? protein in group A,B,C and D was(0.802 ± 0.152)(0.897 ± 0.085),(0.479 ± 0.024)(0.536 ± 0.013),(0.583 ± 0.011)(0.487 ± 0.024),(1.184 ± 0.244)(1.684 ± 0.063)after 7 and 14 days of intervention.After 7 days of intervention,the expression of IL-1 ? protein in group A,B and C decreased significantly,compared with group B and C,except that there was no significant difference between group B and group C(P > 0.05),the difference between other groups was statistically significant(P < 0.05);after 14 days,the expression in group C continued to decline,and the expression in other groups increased significantly,compared with group D,except that there was no significant difference between group B and group C The difference among the other groups was statistically significant(P < 0.05).A.There was no significant difference between group B and group C(P > 0.05).There was significant difference between group D and group B(P < 0.05).Conclusion:(1)combination of PRP and BMAC can promote tendon repair and fibroblast proliferation;(2)combination of PRP and BMAC can better promote tendon I and III The synthesis of type C collagen can accelerate the repair ability of tendon fiber;(3)the combination of PRP and BMAC or BMAC alone can better down regulate the expression of IL-1 ? protein,so as to control the inflammatory response,reduce the inhibition of IL-1 ? on the synthesis of collagen by tendon fibroblasts,and reduce the degradation of extracellular matrix,so as to inhibit the process of tendon pathological changes. |
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