Abstract
Abstract: :
Purpose: Keratoconjunctivitis Sicca (KCS), dry eye syndrome, is characterized by ocular discomfort, ocular surface damage, and an abnormal tear film. KCS is a common reason people visit an eye care specialist. Chronic conjunctival inflamation and epiththelial keratinization are histopathologic features of KCS. We have reported expression of cytokeratin type 3 in the conjunctival epithelia of KCS patients (Ye, et al. ARVO, 1999). The purpose of this investigation is to identify and compare conjunctival epithelial keratin detection using electron microscopy and immunohistochemistry. Methods: Conjunctival epithelial cells were obtained from 10 patients with KCS using Dacron swabs. The swabs were immersed in 0.5ml of PBS. One portion was spun down using a Cytopro cytospin for immunohistochemistry using avidin-biotin complex immunoperoxidase technique. Primary antibodies were CK10 and human keratin. The other portion was centrifuged, the supernatant decanted, and the pellet fixed in 2.5% Gluteraldehyde. The pellet was then processed through ascending alcohols and propylene oxide and embedded in Ladd LX-112 epoxy resin. Thin sections were then taken and stained with uranyl acetate and lead citrate and observed by Transmission Electron Microscopy (Joel 1010). Results: Immunohistochemistry demonstrated keratin expression in all specimens with positive intracellular CK 10 staining. The intensity and density of CK 10 staining correlated with the severity of keratinization observed using routine light microscopy. In contrast, it was difficult to find intact conjunctival epithelial cells by electron microscopy. Most cells showed degenerative changes with loss of cytoplasmic microorganelles. 70-90 angstrom cytoplasmic filiments compatible with cytokeratin or cytokeratin-like structures were seen in some epithelial cells. The number of intracellular keratin-like structures seemed to associate better with the intensity rather than the density of CK 10 staining. Conclusion: Both immunohistochemical staining for CK 10 and electron microscopic examination for keratin filiments can demonstrate conjuntival epithelial keratinization in KCS, however immunohistochemistry is a better technique. The findings are consistent with evidence of keratinization seen in patients with KCS.
Keywords: 472 microscopy: electron microscopy • 365 conjunctiva • 434 immunohistochemistry