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KMID : 0350519920450020609
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Journal of Catholic Medical College
1992 Volume.45 No. 2 p.609 ~ p.621
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The Effects of Hypertonic Solutions on Ultrastructural Changes of Superficial Conjunctival Epithelium in Rabbits
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Abstract
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It is well known that aside from goblet cells and the lacrimal gland there is a third source of mucus secretion on to the surface of the conjunctiva. Deducing from transmission electron microscopy the superficial cells of the epithelium make a
mucoprotein with long chemical chains and package it in the subsurface vesicles. This content is a particular mucoprotein, the glycocalyx which participates in the elaboration of the cell coar and might be serving as an intermediary on the
fixation
of
overlying mucus to the epithelial surface. The epithelial surface is probably the most potent force on maintaining the stability of the tear film and it is here that the adhesive force must act. Epithelial cell integrity is essential for the
stbility of
the tear film especially in dry eyes.
Elevated tear film osmolarit is a final common pathway for the development of many types of "dry eyes". Tear film osmolarity may increase due to decreased tear secretion and/or increased tear film evaporaton.
The aim of this study is to evaluate the morpholigic effect of hyperosmolarity, equivalent to that seen on keratoconjunctivitis on conjunctival surface epithelium of rabbits.
Hypertonic solutions were prepared by a commercially available balanced salt solution(BSS, Alcon), and adjusted to desired final concentrations of 300, 330, and 360 mOsm/1. New Zealand white rabbits weighing 2-3kg were anesthetized, and a
conjunctival
well which was made by elevating the lids and nictitating membrane, was filled with 1 ml of the test solution. The conjunctival sac was submerged in a bathing solution that was exchanged for same fresh every hours for 3 to 6 hours, In twelve
experimental trials, BSS concentrated to 330, 360 mOsm/1 was used to bathe ocular surface for 3 and 6hour periods, respectively. The contralateral twelve eyes bathed in isotonic BSS served as control. Immediately after conjunctival bathing,
biopsy
samples were taken from inferonasal bulbar conjunctiva. The biopsy samples were stained with ruthenium red stock solution contrasted with uranyl acetate and lead citrate, and the experimental specimens and their (?) in a transmission electron
microscope(Joel 1200 EX, Japan). And the (?) by an image analysis system(Kontron, West Germany).
(?) follows:
(?) of bathing in 330 mOsm/ 1 solution, the subsurface vesicles were observed in (?)in number compared to the control group. After 6 hours of bathing in 330 (?) the vesicles increased in number compared to the 3 hour group.
(?) of bathing in 360 mOsm/1 solution, the vesicels were morphologically enlarged(?) compared to the control group. After 6 hours of bathing in 360 mOsm/1(?) were not morphologically changed compared to the 330 mOsm/1 group.
(?) analysis system, after 3 hours of bathing in 360 mOsm/1 solution, the vesicles(?) by three times in total volume compared to the control group(P<0.05). After (?) in 330 mOsm/1 solution, the vesicles significantly icreased in total volume by
(?)
pared to the 3 hour group(P<0.05).
(?) specmens, the conjunctival epithelial cells had widende intercelular spaces (?) manifested by decreased cytoplasmic density, and the microvilli to towards the (?) did not appear to be reduced by increasing osmolarity, although their shape(?).
(?) suggest that subsurface vesicles increase early in number and total volume in (?) at a later time the altered subsurface vesicles by the hyperosmolarity will in(?) of mucus content. And the conjunctival epithelium would lose the capacity ot
(?)
and
lack the specific sites of fixation for these mucoproteins.
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