Abstract
Abstract: :
Purpose: Claudins, important structural and functional components of tight junctions (TJ), are essential for the paracellular transport through interactions with other membrane proteins. Defects in claudins are causatively associated with a variety of human diseases, demonstrating that they play a key role in human physiology. The aim of the present work is to evaluate the expression and behaviour of claudin-1 in the conjunctival epithelium of normal subjects and dry eye patients. Methods: Conjunctival impression cytology specimens were obtained from 10 healthy volunteers (age range 45-55 years) and 20 dry eye patients (10 Sjögren’s syndrome and 10 non-Sjögren patients; age range 48-53 years). Specimens were obtained by means of Millipore filters (pore size 0.22 mm); the specimens were then transferred onto a polylisinate slide and fixed with a buffered 4% paraformaldehyde solution. They were then processed for routine indirect immunofluorescence. An antibody against the C-terminus portion of human claudin-1 (∼22 KDa – MH25 Zymed) was used. The specimens were observed and photographed with a confocal scanning laser microscope LSM 510 Zeiss. Results: In specimens from healthy volunteers claudin-1 is expressed along the cellular margins, showing a characteristic linear fluorescent signal. In specimens from dry eye patients, both Sjögren and non-Sjögren, the immunofluorescent signal was different from that of normal subjects: the signal on the cellular margins was, in fact, often interrupted and arranged in a punctiform rather than linear pattern; in other instances, the signal was located in the cytoplasm with a neat demarcation along the perinuclear cisterna. Conclusion: Our results show that Claudin-1 is expressed in TJ of the human conjunctival epithelium an that its pattern is modified in dry eye patients.
Keywords: 365 conjunctiva • 376 cornea: tears/tear film/dry eye