The Role Of Epithelium In The Corneal Transplantation Rejection

Part ⅠThe effect of different concentration alcohol on rat corneapurpose:To study the effect of different concentration alcohol on cornea and choice the safe concentration to make the corneal epithelium flap.Methods: Wistar rats were choosen to involve this study. To determine the effect of dilute alcohol on cornea, 3.5mm diameter center corneal epithelium were exposed to different concentration alcohol for different time as follow.1) the corneal epithelium were exposed to 15％ to 40％ alcohol for one minite.2)the corneal epithelium were exposed to 20% alcohol for 30 seconds,1 minite and 2 minites.3) the corneal epithelium were exposed to 20% alcohol for 1 minite and observation for 3 days.4) choosing a safe concentration to make the epithelial flap. The cornea above experiments were stained by HE and PAS for light microscope examination . The epithelial flap , epithelium-removing cornea and the cornea exposed to 20% and 40% alcohol were observed by electronic microscope. And immunohistochemistry staining for LGs was made to evaluate the immunologic influence of alcohol to corneal.Results: Exposed to 15% alcohol for 1 minite and 20% alcohol for 30 seconds ,there was not obvious effect on the cornea;Exposed to 20% alcohol for 1 minite,the nuclear of surperficial epithelium concentrated and the connection of surperficial epithelium became loose,and these damage recovered three days later ;exposed to 20% alcohol for 2 minites and 30% alcohol for 1 minite ,the bullous occurred and the nuclear of surperficial epithelium and the wing epithelium layer concentrated, at the same time the basement membrane broken at some point; exposed to 40% alcohol for 1 minite,the area of bullous was enlarged, the connection of surperficial epithelium became loose and the membrane of cells were disrupted, the nuclear of basal epithelium concentrated, there were vacuoles in the basal epithelium cells,the basement membrane broken,but the stroma and endothelium kept normal.It is easy to make the epithelial flap exposed the epithelium to 20% alcohol for 1 minite,and the plane of cleavage was at the superficial part of the basement membrane.The expression of LGs did not change by 20% alcohol.Conclusions:1)exposed to dilute alcohol, the connection of superficial epithelium became losse, bullous occurred, nuclear of epithelium concentrated,but the stroma and endothelium kept intact in this study. And these effects were in dose- and time-dependent manner.2) exposed to 20% alcohol for 1 minite, the damage of epithelium was minor and can reproduce. So it was relatively safe to make epithelial flap by this way.Part ⅡThe role of epithelium in the corneal transplantation rejectionPurpose:To study the role of epithelium in the corneal transplantation rejection and determine whether epithelium-deprived corneal allografts covered with syngeneic epithelium can promote the survival of corneal allografts.methods: 120 inbred rats received an allo(F344→Wistar) or isogeneic graft(Wistar→Wistar). the rats were devided to six groups randomly. A group :Full-thickness( donor epithelium-containing) isogeneic corneal graft; B group : donor epithelium- deprived (the graft without epithelium) isogeneic corneal graft; C group : reciepient epithelium-containing (donor stroma covered with reciepient epithelium) isogeneic corneal graft; D group: Full-thickness( donor epithelium-containing) corneal allograft; E group : donor epithelium- deprived (the graft without epithelium) corneal allograft ; F group : reciepient epithelium-containing (donor stroma covered with reciepient epithelium) corneal allograft. Slitlamp examination were made to record the rejection index everyday to 4 weeks postoperation. During the different time point the rats were killed and enucleation for histological observation including HE and immunohistochemistry staining for VEGF, LGs,CD4, CD8 and RT1B.Results: The corneal graft of autograft group kept clear without rejection at the end of the observation period .In these three groups the neov...