| Objectives:Exploring the method of preparing a composite cartilage supported graft using injectable platelet-rich fibrin(i-PRF)mixed with cartilage particles and covered with high-density porous polyethylene(HPDE).Methods:1.i-PRF acquisition:Extract 10 mL of heart blood from adult New Zealand white rabbits and centrifuge for 3 min at 700 rpm to layer it.Extract i-PRF from the clear liquid and use it within 15 minutes before coagulation.2.Obtain cartilage particles:Cartilage particles can be obtained by cutting rabbit ear cartilage into particles of about 1-2mm3.3.Preparation of supporting grafts:The grafts were divided into four groups,namely group A(HPDE alone),group B(i-PRF+HPDE group),group C(cartilage particles+HPDE),and group D(i-PRF+cartilage particles+HPDE group).4.Living experiment:A total of 18 adult New Zealand white rabbits were used.The grafts prepared in Groups A,B,C,and D were embedded into the subcutaneous left anterior,right anterior,left posterior,and right posterior positions of New Zealand white rabbits,respectively.The experimental animals were randomly divided into three groups and fed in a single cage.The graft was removed at 4,8,and 12 weeks after surgery.5.Histological observation and evaluation:The growth of surface tissue and the fixation of cartilage particles were observed with naked eyes in each group.Observing the microstructure of the internal pores of HPDE material,as well as the surface and pores of the grafted object through electron microscopy.HE staining was used to observe the growth of fibrous vascular grafts in the internal pores of the material and the degree of articulation of cartilage particles.The graft was stained with safflower O-solid green to facilitate observation of the degree of articulation of cartilage particles.Masson staining was used to observe the growth of collagen fibers entering the internal pores of the graft.Immunohistochemical methods were used to observe the joint extent of the graft cartilage particles.The growth level of blood vessels in the internal pores of the graft was observed by immunofluorescence.Results:1.Macroscopic observation of the grafts:Four weeks after surgery,the surfaces of the four groups of transplanted objects were coated with tissue,but the amount of tissue was small and the color of the tissue was lighter.The surface structure of group B materials is more than that of group A.Group D had more cartilage particles and more tissue on the surface of the material than group C.At 8 weeks after surgery,the surface tissue of the graft in the four groups increased and the tissue color was redder than before surgery.The color of the surface tissue of the material in Group B is slightly red than that in Group A,and Group D is slightly red than that in Group C.At 12 weeks after surgery,all grafts had a tissue coating on their surfaces.The surface structure of Group B is significantly more than that of Group A,and the color is more red.After removing the graft from the skin,group D exhibited more cartilage particles than group C,and the surface tissue color was redder than group C.2.Electron microscope observation:HPDE materials have a porous structure and interconnected pores.At 4 weeks after surgery,the surface of each group of support grafts was surrounded by fibrous blood vessels that had grown into the support holes.At 8 and 12 weeks after surgery,the surface fiber and blood vessels supporting the transplanted object continued to increase,and the structure of the inner pore fiber and blood vessels also increased.At the same time,the fibrous vascular tissue in the material hole of the graft in Group B was denser than that in Group A,and the connection of the cartilage particles of the graft in Group D was tighter than that in Group C.3.HE staining and Saffron O-Solid Green staining:At 4,8,and 12 weeks after surgery,compared to Group C,the graft in Group D contained i-PRF composite cartilage support,and its cartilage particles could connect to form blocks earlier than Group C.In addition,the cartilage connections in Groups C and D became more tight as the graft was removed from the animal’s back for longer.4.Immunohistochemistry:At 4,8,and 12 weeks after surgery,the content of type Ⅱcollagen in group D(containing i-PRF)was higher than that in group C.This indicates that cartilage grafts containing i-PRF can make cartilage grow faster and allow for faster connections between cartilage particles.5.Masson staining:At 4,8,and 12 weeks after surgery,the graft wrapped in I-PRF in Group B showed more dense collagen fibers in the pore diameter than in Group A.6.Immunofluorescence:At 4,8,and 12 weeks after surgery,group B grafts encapsulated with i-PRF showed more dense neovascularization in their apertures than group A.Conclusions:1.Compared to simply embedding HPDE materials,the group containing i-PRF had more collagen fiber blood vessels in the material pores.2.The composite cartilage particles formed by i-PRF mixed with cartilage particles can support the cartilage particles of the transplanted object and connect into pieces faster.At the same time,the fixed position of cartilage particles is good,which has clinical value and is worth further research. |
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