Study Of The Effects Of Thalidomide On The Immune Rejection After Ostrich-rabbit Heterolamellar Corneal Transplantation

【Objective】Immunological rejection the immune response and tissuedamage mediated by T lymphocyte is the main cause of the failure of cornealtransplantation. Some standards about immune rejection after cornealtransplantation are as follows: inflammatory cell infiltration; edema ,opacity of graft and the entering of new vessels. Among those, cornealnew vessels(CNV) is regarded as the most important factor that leads tothe missing of corneal transparency. It is a tough problem we areconstantly faced with that we have to look for valid drugs to prevent andinhibit immunological rejection. Therefore some of the overseas scholarssuggest that the combination of anti-new vessels drugs withimmunosuppressive ones would develop a very promising prospect intreating immune rejection. In the past study, thalidomide(THD),werethought to have effects of anti-inflammatory , anti-tumor ,anti-neovascularization and immunomodulation, and shown to prolong graftsurvival in experimental skin, renal, cardiac and bone marrowtransplantation. We establish the model of ostrich-rabbit heterolamellarcorneal transplantation and apply THD to the rabbits, then observe thepathological change of corneal grafts, the VEGF expression changes atgene and proteinum level, and the positive rate change of CD4+,CD8+ Tlymphocyte of peripheral blood. We aim to probe into the function 6第二军医大学 硕士学位论文 英文摘要mechanism of CNV inhibition and immunomodulation so as to providetheoretical foundation for clinical application of THD. 【Methods】32 healthy New Zealand rabbits(≦8 weeks)that receivedlamellar corneal transplants (ostrich donors) were divided into fourGroups (eight rabbits in each): Group A received no treatment and servedas allograft controls; Group B (ostrich to rabbit ) received no treatmentand served as xenograft controls; Group C (ostrich to rabbit ) were treatedwith THD; and Group D (ostrich to rabbit ) received prednisone. The timeof treatment and observation were both 4 weeks. We observed theinflammatory reaction of the grafts under the slit-lamp microscope everyday and graded the grafts by Holland standards. One corneal graft of eachGroups was excised for pathological examination postoperative 2,3,4 week.Postoperative 4 week, all the remained corneal grafts were excised forimmune histochemistry and RT-PCR to detect the expression ofneovascularization factor VEGF. We measured the length, number, clockhour of CNV and radius of cornea to calculate the area of CNV before weexcised the grafts. The peripheral blood of rabbits was takenpreoperative, postoperative 1 week,2 week,3 week,4 week to be detectedpositive rate of CD4+ and CD8+ by flow cytometry 【Results】 1.Mean survival time(MST) of rabbit corneal grafts in each Group is :Group A 28 days,Group B 15.83±2.483 days,Group C 28 days,Group D 23.33±1.211 days. The difference between C and B, C and D, B and D isstatistically significant(P﹤0.0001),meanwhile there is a significantdifference between A and B(P﹤0.0001) 2. Light and electron microscope results of postoperative 2 week, 3week, 4 week corneal grafts: 7第二军医大学 硕士学位论文 英文摘要 Group A: Postoperative 2 week, a great deal of vacuoles formed in basalcell of corneal epithelium. There was some slight neutrophil infiltration,no new vessels, some raritas and disordered collagen fibers(CF) insuperficial substantia propria layer under epithelium around the juncturebetween donator and receptor; Postoperative 3 week, neutrophils increased,a small quantity of CNV occurred, and CF aligned regularly;Postoperative 4 week, the quantity of inflammatory cells and blood vesselsfurther increased, and CF aligned more regularly. Group B: Postoperative 2 week, a deal of vacuoles formed in basal cellof corn...