Acute ocular effects of mustard gas: Ultrastructural pathology and immunohistopathology of exposed rabbit cornea

Whole-body exposure to sulfur mustard (HD) produces cutaneous, respiratory and ocular impairment. Of these, ocular damage causes the most immediate in capacitation. Heretofore, characterization of HD ocular toxicity has been l argely limited to gross and histological observations. In the present study we explore histological, ultrastructural and immunopathological acute effe cts of HD ocular exposure and establish correlations with HD toxicity data already documented for dermal exposure. Anesthetized rabbits were exposed t o 0.4 rhol of liquid HD placed directly on the cornea, Animals were euthani zed at 6, 9 and 24h post-exposure and the eyes were enucleated and processe d for histopathology, ultrastructural and immunoperoxidase study. At 6 and 9h, the most prominent histological feature was nuclear pyknosis, necrosis and loss of polarity of corneal epithelial basal cells to the exclusion of other epithelial cells. At 24 h, all corneal epithelial cells presented deg enerative changes, with the epithelium eventually detaching from the underl ying basement membrane at the level of the lamina lucida, Microblisters, a characteristic HD-induced skin pathology of the basement membrane zone of a nimals, were absent in this corneal study. Edema, degenerating fibroblasts and inflammatory cellular infiltrates were persistent stromal responses, Im munopathological effects included changes In antigenicity of bullous pemphi goid protein, laminin, desmosomal protein, Ki67 and p53, These morphologica l and immunopathological effects of corneal exposure to HD appear to be lar gely consistent with that previously reported for dermal exposures, perhaps providing shared anatomical considerations for the development of specific HD prophylaxis and therapy.