| Background:Venous ulcer is one of the serious and refractory complications of lower extremity venous disease.The incidence of venous leg ulcers is higher[1],and the healing period is long,the healing rate is low,and it is easy to relapse.The recurrence rate can be as high as 70%[2]There is still no effective cure for clinical treatment.With the rapid development of biomaterial technology,a large number of biomaterials with excellent performance have shown great clinical application potential.Electrospun nanofibers with polylactic acid/gelatin blends are one of the most ideal material combinations for soft tissue repair applications[3-4].It has been reported in the literature for the repair of brain dura mater and can promote cell fast Migration and colonization to achieve tissue regeneration and repair[5].However,electrospun polylactic acid/gelatin nanofiber materials have few studies on skin wound repair and chronic ulcer repair,and the application effect is unknown.The clinical application prospects still need further exploration.Objective:1.Using a 3D printing handheld electrospinning machine to bio-manufacture polylactic acid/gelatin nanofiber membrane,evaluate the properties of membrane materials and in vitro biological properties,and explore the repair effect of polylactic acid/gelatin nanofiber membrane on animal skin wounds.2.Feasibility evaluation of clinical application of polylactic acid/gelatin nanofiber membrane in wound repair of patients with varicose veins of lower extremityMethods:Part I:（一）In vitro evaluation of the properties of hand-held electrospun PLA/gelatin polymer degradable nanofiber membrane materials.Specific method 1Material property evaluation:Polylactic acid/gelatin degradable nanofiber membrane was prepared by self-made 3D printing handheld electrospinning equipment,and its contact was detected by electron microscopy,Fourier transform infrared spectroscopy（FTIR）and X-ray diffraction（XRD）.Angle,water vapor transmission rate material characteristics;2 biological characteristics evaluation:concentration of 100%,50%,25%polylactic acid/gelatin degradable nanofiber membrane extract cultured fetal rat fibroblasts,using CCK-8 The cytotoxicity assay was used to evaluate the residual solvent toxicity of the material;the fetal rat fibroblasts were co-cultured with the polylactic acid/gelatin degradable nanofiber membrane（experimental group）,the individual cell culture was set as the control,and the Alamar blue method was used to detect cell proliferation,live/dead staining.Cell viability was observed and cell morphology was observed by scanning electron microscopy.（二）Animal experiment:Hand-held electrospun polylactic acid/gelatin degradable nanofiber membrane in the repair of skin defect in Balb/c mice.Eighteen Balb/c mice were selected and a full-thickness defect of 2 cm in diameter was made on the back.The results were divided into experimental group and control group by numerical random grouping.The experimental group was subjected to hand-held electrospinning in-situ polylactic acid/gelatin degradable nanofiber membranes,and the gauze was wrapped.The control group was wrapped with ordinary gauze.The defect was taken 8 weeks after operation,and hematoxylin-eosin and Masson staining were performed.Observe the repair effect of the defect skin.Part II::According to the inclusion criteria and exclusion criteria,60 patients with varicose veins of the lower extremity who were admitted to the vascular surgery of a third-grade hospital in Anhui Province from January 20 to December 2018 were randomly divided into several groups.For the experimental group and the control group,30 patients in each group,the experimental group used PLA/gelatin nanofiber membrane;the control group used traditional oil gauze or vaseline.The wound healing rate,healing time,dressing times,wound pain score,comfort,ease of operation,and safety were recorded and compared between the two groups.Six months after wound healing,the Vancouver Scar Rating Scale was used to evaluate the repair effect.Results:1.（1）Polylactic acid/gelatin degradable nanofiber membrane contact angle is（32.68±5.68）°,is a hydrophilic material,suitable for cell adhesion;24 h water vapor transmission rate（4.21±0.11）×103 g/m2 To meet the requirements of skin dressings;different concentrations of PLA/gelatin degradable nanofiber membrane extracts have no obvious cytotoxicity;（2）experimental group fetal rat fibroblasts in PLA/gelatin nanofilm growth characteristics and two-dimensional（2D）There was no significant difference in cell viability between the control cells（P>0.05）,but with faster proliferation rate and longer proliferation time.Hematoxylin-eosin and Masson staining showed that the skin wounds of the experimental group were healed in the whole layer,the material degradation was complete,and some hair follicles were regenerated.The skin of the control mice did not reach full-thickness healing.2.The wound healing rate and patient satisfaction of the experimental group were higher than those of the control group（P<0.05）.The time of wound healing,the number of dressing changes,wound pain,secondary wound dressing,and ease of operation were significantly lower than those of the control group（P<0.05）.6 months after the wound healing,the score was scored according to the Vancouver Scar Rating Scale.The control group was（9.90±1.24）,which was significantly higher than the test group（7.43±1.04）（P<0.05）.During the trial,the two groups of patients No adverse reactions were observed.Conclusions:1.Through in vivo and in vitro experiments,PLA/gelatin nanofiber membranes have superior material properties such as good mechanical properties,hydrophilicity,gas permeability and non-cytotoxicity,as well as excellent biocompatibility.PLA/gelatin nanofiber membrane can achieve rapid and in situ repair of animal skin defects,showing potential application space in the repair of skin wound defects.2.Polylactic acid/gelatin nanofiber membrane is safe and effective,which can shorten the wound healing time,reduce the frequency of dressing change,reduce the pain and secondary trauma during wound dressing change,and is convenient for clinical medical staff to improve the patient’s Comfort and satisfaction have significant clinical value. |
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