| Tendon repair and regeneration usually go through three stages:inflammation stage,proliferation or repair stage,and remodeling stage.However,due to the difference of anatomical site or local environment,the mechanism and healing potential of acute tendon tear or degenerative tendon injury are different.The rotator cuff tendon injury in the synovium is not easy to heal spontaneously,mainly because the tendon injury in the synovium often occurs at the tendon-bone interface,and the tendon-bone interface is not easy to be reconstructed.At present,implanting patches at the injury is an effective method,but the patch materials still have the following defects:lack of directional growth,migration and differentiation of cells,lack of mechanical properties and so on.The injury of Achilles tendon is extrasynovial,it is easy to form fibrous tissue and cause adhesion,which hinders the repair of Achilles tendon.The use of physical barrier to prevent adhesion is a hot spot at present,but there are also some shortcomings,such as poor hydrophilicity of the membrane,easy displacement and suture fixation.In this paper,based on the optimization of electrospinning parameters,fiber patches with different PLLA/HA mass ratio and multilayer composition gradient anti-adhesion fiber films were prepared,and their properties were studied.The main research contents are as follows:(1)The rotator cuff patches with different PLLA/HA content were prepared by solution electrospinning,and the physicochemical properties of rotator cuff patches were characterized.Isolate rat bone marrow mesenchymal stem cells(BMSCs)and co-culture with rotator cuff patch to evaluate the cytocompatibility and osteogenic induction ability of each patch.The results showed that the porosity and hydrophilicity of the fiber increased with the addition of HA.However,due to the partial agglomeration of HA,the mechanical properties of the fiber patch with higher HA content were worse.The results of CCK-8 and dead/living cell staining showed that BMSCs could proliferate well and grow in a certain orientation on the rotator cuff patch of each group.In addition,the addition of HA could also increase the expression of ALP in BMSCs.The prepared PLLA/HA mixed component fiber patch has good cytocompatibility,the orientation of the fiber can guide the directional growth of cells to some extent,and enhance the osteogenic induction ability of BMSCs.According to the comprehensive analysis of the properties of each patch,the mass ratio of PLLA to HA is 3:1,which is expected to be an ideal patch material in rotator cuff repair.(2)The multilayer gradient Achilles tendon anti-adhesion membrane was prepared by solution electrospinning,and each layer of the fibrous membrane was characterized and analyzed to explore the changes of physical and chemical properties from the outer layer to the intimal layer.Rabbit fibroblasts were isolated and cultured and inoculated into the anti-adhesion membrane of Achilles tendon.The effects of different layers of fibroblasts on the proliferation and adhesion of rabbit fibroblasts were detected by CCK-8.The results showed that the diameter of the fiber membrane decreased gradually from the outside to the inside,the pores relatively and hydrophilicity increased gradually,and the biocompatibility was good.CCK-8 results showed that the outermost PLLA fiber layer could effectively inhibit the adhesion and proliferation of fibroblasts around the tendon.The inner layer was gradually hydrophilic and adhered more closely with the damaged site,which means not to need surgical suture and fixation,This can reduce the complexity of the operation,and has great potential in the prevention of peri-tendon adhesion. |
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