Preparation And Biocompatibility Of Electrospinning PDLLA/?-TCP/Collagen For Peripheral Nerve Regeneration

Peripheral nerve injuries often happen in our daily life,which are caused by accidents,fires and their own genetic diseases Autologous nerve transplantation can not meet the actual needs because of its limitations.Single kind of material nerve conduit can not repair nerve injury well,so the study of composite nerve conduit becomes very important.The compound nerve conduits can choose different material according to the specific condition of peripheral nerve damage and make different sizes to meet the actual demands of nerve repair.In this paper,we used polylactic acid(PDLLA),calcium phosphate(?-TCP)and Icollagen(Collagen).PDLLA,?-TCP and Collagen dissolved in organic solvents(dichloromethane: ethyl acetate=7:3),and PDLLA/ ?-TCP/Collagen composite catheters films were prepared by electrostatic spinning.PDLLA,PDLLA/?-TCP were prepared following the same way.The samples were tested through Infrared Spectra Test,Scanning Electron Microscope,Tensile test and degradation experiment in vitro;Culturing cell is to analyze the toxicity of films,and extracting rabbit fresh blood is to test the rate of hemolysis of the films;After the films safety performance reached the national standard of biomedical materials after implantation,the films were implanted into rats subcutaneous tissue for two weeks,and the subcutaneous tissues that contact with the films were collected with immunohistochemical staining(TNF-?)analysis;The samples were used for the repair of rat 10 mm sciatic nerve defect in right leg and the autograft group was set as the control experiment,then the appearance of rats were observed within three months.The gastrocnemius muscle and the new nerve were removed after three months raising,the middle of gastrocnemius muscle was cut for the research of HE staining and the test the muscle atrophy rate.the middle parts of newborn nerve is used for HE staining,then immunofluorescence staining(DAPI,mouse,anti-neurofilament 200)and uranyl acetate and lead citrate staining were made.Through the infrared analysis,three groups of samples showed successfully.With the observation of Scanning Electron Microscopy,the film fibers were kept in uniform and thin size.PDLLA,PDLLA/?-TCP and PDLLA/-TCP/Collagen hole diameter were 2.51 + 0.53?m 2.72 + 0.61?m 3.01 + 0.74?m Separately,which showed semi-permeable structure(0 < dia < 10 ?m),and the structure was available for nutrients to turn into from outside,and could block the lymphoid tissue to enter;each group had certain mechanical property;The degradation experiment of PDLLA/?-TCP/Collagen quality shows the loss rate(35%)in three months,Which had appropriate degradation properties,and the degradation pH value maintained in neutral.The degradation rate and pH value in PDLLA/?-TCP/Collagen and control group were better than PDLLA,and PDLLA/?-TCP can provide temporary environment for repair;Culturing RSC96 cells was used in cytotoxicity test.The cell toxicity of each materials showed very safely,and the hemolysis rate of materials were small through hemolysis test which had reached the national standard for medical implant material;PDLLA/?-TCP/Collagen rat's right leg toe ulcer and pain recovery is faster than pure PDLLA and PDLLA/?-TCP,but slower than the autograft group during three months.The inflammatory reaction in the PDLLA/?-TCP/Collagen was less than PDLLA and PDLLA/?-TCP,which showed the biocompatibility was better.The gastrocnemius muscle that was analyzed in PDLLA/?-TCP/Collagen which showed the rate of gastrocnemius atrophy in PDLLA/?-TCP/Collagen was less than that in PDLLA and PDLLA/?-TCP(P < 0.05),but was larger than that in autotransplantation group(P > 0.05).The density of cells(blue)and neurofilaments(green)in PDLLA/?-TCP/Collagen and autograft group were higher than PDLLA and PDLLA/?-TCP;The average diameter of the gastrocnemius muscle cells in PDLLA/?-TCP/Collagen was larger than PDLLA and PDLLA/?-TCP(P < 0.05),close to autologous transplantation group(P > 0.05).The fiber morphology,axonal diameter and myelin sheath thickness of newborn nerve in PDLLA/?-TCP/Collagen were better than those in PDLLA and PDLLA/?-TCP(P < 0.05),which were close to autotransplantation group(P > 0.05).