Experimental Study About Prevention And Treatment Of Post-traumatic Orbital Tissue Adhesion

[Objective]To study the feasibility to establish a rabbit model of orbital tissue adhesion after trauma,and to observe the influence of soft tissue adhesion after orbital trauma by Fuorouracil(5-Fu),Fuorouracil Sustained Release for Implant(FSRI) and chitosan membrane(CM).[Methods]Part1:There were 5 rabbits(10 orbits),adopted to established the model.Superior fornix conjunctiva was cutted to find superior rectus and corresponding periosteum after normal degermation and anesthesia.After clamping tendon of superior rectus about 1 minute,orbital injury was made between superior rectus(0.5cm×0.5cm) by scraping 10 times and corresponding periosteum(1cm×1cm) by scraping 20 times.2 weeks later,to observe the formation of adhesion.Part 2:There were 4 groups,Group A(5-Fu group),Group B(FSRI group),Group C(CM group) and Group D(control group),5 rabbits(10 orbits) per group.To establish the mode by above-mentioned at frist,then segregate the adhesion by operation after 2 weeks of trauma,Group A aslo locally applyed with 5-Fu(25mg/ml) 10 min.Group B implanted FSRI(20 mg) locally.Group C implanted the membrane between the lesion.Group D only used isotonic Na chloride locally with 10 min.4 weeks later,to observe the formation of adhesion,the quantity of fibroblasts,aslo to analyze the condition of collagen fibers(IOD value in unit area and relative area),the healing of conjunctival incision,effects of retina and optic nerve were observed.[Results]Part 1:2 weeks after operation,the adhesion tissue was formed on the surface of superior rectus,fibers were pycnotic,proliferation of fibroblasts was obvious,some of them became Fusiform,inflammatory cells and new vessels were visible.The quantity of fibroblasts in unit area were 240.00±32.44 /mm²,IOD value in unit area and relative area of collagen fibers were 0.2589±0.0722,52.92%±18.59%, (Z₁=0.994,Z₂= 0.658,Z₃= 0.821,P＞0.10),the data of three groups were similar to normal distribution.Part 2:Adhesion degree evaluation showed there were 3 orbits with 2 score,7 orbits with 1 score in Group A,4 orbits with 2 score,6 orbits with 1 score in Group B, 2 orbits with 2 score,5 orbits with 1 score and 3 orbits with 0 score in Group C,10 orbits with 3 score in Group D.There was a statistically significant difference (T₁=55.00,T₂=55.00,T₃=55.00,P＜0.01) in adhesion degree between three experimental groups and control group.The quantity of fibroblasts in unit area were 96.4444±32.01788 /mm² in Group A,78.4444±35.23738 /mm² in Group B,80.0000±20.81727 /mm² in Group C,225.4444±52.35882 /mm² in Group D.There was a statistically significant difference(t₁=17.974,t₂=19.495,t₃=21.641,P＜0.01) in quantity of fibroblast between three experimental groups and control group.IOD value in unit area of collagen fibers was 0.3046±0.0862 in Group A,0.1836±0.0511 in Group B,0.2152±0.0755 in Group C,0.2739±10.1262 in Group D.There was a statistically significant difference(t₁=4.694,t₂=2.824,P＜0.01) in IOD value in unit area between Group B and Group D,Group C and Group D.Aslo there was a statistically significant difference(t₁=8.530,t₂=5.510,P_1,2＜0.01;t₃=2.45,P₃＜0.05) between Group A and Group B,Group A and Group C,Group B and Group C.Relative area of collagen fibers was 31.7718%±8.51069%in Group A,32.7368%±9.89077% in Group B,33.2704%±8.12048%in Group C,39.6956%±11.55263%in Group D. There was a statistically significant difference(t₁=3.905,t₂=3.235,t₃=3.217,P＜0.01) in relative area between three experimental groups and control group.The healing of conjunctival incision was A degree in all groups.The structure of retina and optic nerve were not changed in histopathology.[Conclusion]1.It's feasible to establish orbital adhesion model,through clamping and scraping superior rectus and corresponding periosteum;2.Applyed with 5-Fu simply in impaired region,could inhibit the proliferation of fibroblasts and decrease the synthesis of collagen fibers.When implanted FSRI,the synthesis of collagen fibers could decrease further,both were effective on preventing adhesion after orbital trauma;3.CM could inhibit the proliferation of fibroblasts,decrease the synthesis of collagen fibers,was effective on preventing adhesion after the orbital trauma.And the effect of CM is better than 5-Fu,but worse than FSRI;4.5-Fu,FSRI and CM didn't affect the structure of retina and optic nerve.All didn't affect healing of conjunctival incision.