Pathologic changes of corneal lesions in rabbits after ocular exposure to mustard gas

Objective To observe the pathologic changes of corneal lesions in rabbits induced by mustard gas and changes of lymphocytes in the pathologic development so as to discuss the role of lymphocytes in the pathogenic process.Methods Thirty-five New Zealand white rabbits were randomly divided into experiment group and control group according to the random number table.In experiment group,rabbits were exposed to 0.2 ml of mustard gas liquid (400 μl/L) for a period of 4 minutes and were divided into 6 subgroups at 15 min,2 h,1 w,3 w,4 w,and 8 w after injury.Corneal tissue from each group was collected to detect changes of lymphocytes with aid of HE and immunohistochemical stainings.Results In experiment group,corneal epithelium was dropped totally,basement membrane was exposed,swelling was thickened,matrix layer was loosened and swelled,and collagen fibre was ranged loosely at 15 minutes and two hours ; corneal epithelium appeared multi-layer hyperplastic change in acute restoration period at 1 week; basal corneal epithelium cells appeared irregular column arrangement in chronic inflammation period at 3 and 4 weeks; around 10％ of toxic corneas had delayed reaction with partial corneal epithelium resloughed,fundus membrane appeared,edema thickened,and stroma collagens loosened and swelled at eight weeks.Immunohistochemical Envision staining showed positive expression of plymphomonocytes (CD20,CD45RO,and LCA) inside matrix layer at corneoscleral junction.Conclusions Ocular exposure to 400 μ/L mustard gas for a period of four minutes leads to direct and delayed lesions to cornea,which presents at one week and eight weeks respectively.The lymphocyte-mediated cellular and humoral immunity responses may be involved in the pathogenic process. Key words: Mustard gas;  Cornea ;  Eye injuries ;  Pathology