| Objective: To evaluate the in vivo biocompatibility of fibrin adhesive adhered double-layer corneal stromal lenses as corneal grafts and to further explore the feasibility of using fibrin adhesive adhered double-layer lenses as corneal grafts for lamellar corneal transplantation.Methods:(1)Fifteen healthy clean grade New Zealand white rabbits(30 eyes)were selected for the experiment using self-control.The left eye of the rabbits was used as the control eye and the right eye was used as the experimental eye,and lamellar transplantation was performed on the rabbit experimental eyes.(2)The corneal condition of rabbits was observed by hand-held slit lamp microscope at 7,14 and 28 days after surgery.The observations included that the degree of transparency,edema and corneal neovascularization growth of the rabbit’s corneal transplants in both eyes,the occurrence of inflammatory reaction and rejection reaction in the rabbit’s conjunctiva and cornea;and the coverage of corneal epithelial cells in rabbits was observed by staining with sodium fluorescein staining strips.The first three items of the above observation indexes were recorded as scoring indexes,and the sum of the three scores was recorded as the rejection index.The differences in the scoring results between the two groups were statistically analyzed.(3)Five rabbits were randomly executed on postoperative days 7,14 and 28,and pathological sections were obtained from both eyes and stained with HE to observe the microstructure of corneal tissues in both eyes,including the fusion of corneal graft and implant bed,the absorption of fibrin adhesive between the two lenses,corneal epithelial coverage,inflammatory reaction and the whole corneal structure of control eyes.Results:(1)The postoperative slit lamp observation results of both rabbit eyes:throughout the postoperative period,no rejection phenomenon was observed in the rabbit experimental cornea,the experimental conjunctiva was mildly edematous at 7 days postoperatively and then gradually subsided,at 7 days postoperatively,the experimental cornea was mildly edematous,the transplanted area was not transparent,the transplanted area corneal epithelium did not cover the transplanted piece yet,and the transplanted area corneal fluorescein staining was stained;at 14 days postoperatively,the experimental cornea was less edematous,the transplanted area corneal epithelium basically covered the transplanted piece.The corneal transparency of the transplanted area improved,the epithelium of the transplanted area basically covered the transplanted piece,and the fluorescein staining did not stain except at the suture;28 days after surgery,the corneal recovery of the rabbit experimental eyes was good,the cornea recovered to mild edema,the corneal transplanted piece recovered to basic transparency,and the corneal fluorescein sodium staining only saw a little dot staining;no inflammatory reaction was seen in the whole conjunctiva of the control eye,the cornea maintained a transparent state,and there was no corneal edema The corneal epithelial coverage was good.(2)Biocompatibility scores were1.00(1.00-2.00),1.50(0.75-2.00),and 1.00±0.71 for corneal graft edema at 7,14,and 28 days after lamellar corneal transplantation in rabbit eyes;1.80±0.68,1.30±0.68,and 1.60±0.55 for corneal graft transparency at 7,14,and 28 days after surgery,respectively;and 0.77±0.37,1.00,and 1.60±0.55 for corneal neovascularization at 7,14,and 28 days after surgery,respectively.1.30±0.68 and1.60±0.55;corneal neovascularization scores of 0.77±0.37,1.00(1.00-1.00)and1.00(1.00-1.00)at 7,14 and 28 days postoperatively,respectively;rejection index of 4.00(3.00-5.00),4.00(2.75-5.00),and 3.60±1.14 points.(3)The results of statistical analysis of the scores of experimental and control eyes: the differences in the scores of the degree of transparency,edema,neovascular growth and rejection index between the two groups were statistically significant(P < 0.01)at7 and 14 days after surgery;the differences in the scores of the degree of transparency,edema,neovascular growth and rejection index between the two groups were not statistically significant(P > 0.01)at 28 days after surgery.(4)Histopathological findings: 7 days after corneal surgery in rabbit eyes,corneal epithelial cells had not yet covered the implant,corneal collagen fibers were disorganized,a few neutrophils were infiltrated in the corneal implant,there was a clear demarcation zone between the double-layer lens,the interlayer fibrin adhesive had not yet been absorbed,and the implant adhered well to the recipient corneal tissue.14 days after surgery,a single layer of corneal epithelial cells covered the implant,the arrangement of corneal collagen fibers was still disordered,there were still a few neutrophil infiltrations in the implant,most of the double-layer lenses were fused,most of the interlayer fibrin adhesives were absorbed,and the implant adhered well to the recipient corneal tissue.28 days after surgery,there were 2-3 layers of corneal epithelial cells covering the surface of the implant,corneal collagen was neatly arranged and regular,no neutrophil infiltration was seen in the implant,the fibrin adhesive between the double-layer lens was completely absorbed,the boundary between the two corneal stromal lenses disappeared,the implant was well integrated with the recipient corneal tissue,no obvious boundary was seen,the corneal structure was restored to be similar to the normal corneal tissue structure and morphology;the corneal morphology of the control eye The corneal surface was normal,with multiple layers of corneal epithelial cells covering the corneal surface,neatly arranged corneal collagen fibers,normal structure and no inflammatory cell infiltration.Conclusions:(1)The rabbits were subjected to lamellar corneal transplantation using a bilayer corneal stromal lens constructed with a fibrin adhesive as a corneal graft sheet,and the rabbit eyes recovered well after surgery.(2)Fibrin adhesive-adhered bilayer corneal stromal lenses are biocompatible,have low rejection,and their use as a replacement for corneal implants is feasible.(3)The fibrin glue formed by thrombin solution,fibrogen solution and thrombin solution with a concentration of 500IU/m L has good viscosity and biomechanical strength,and is more suitable for attaching doublelayer corneal stroma lenses to construct corneal transplant materials.(4)Preserving the corneal stromal lens at-20℃ has little effect on the application of lamellar keratoplasty of the corneal stromal lens and can be used in clinical applications. |
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