Purchase this article with an account.
B. Strong, W. Farley, M.E. Stern, S.C. Pflugfelder; Topical Cyclosporin Inhibits Conjunctival Epithelial Apoptosis in Experimental Murine Keratoconjunctivitis Sicca . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2514.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Increased conjunctival epithelial apoptosis has been observed in an experimental murine model of keratoconjunctivitis sicca (KCS.) Topical cyclosporin (CSA) has been noted to reduce conjunctival epithelial apoptosis in chronic canine and human KCS. The purpose of this study is to determine if topical CSA treatment inhibits conjunctival epithelial apoptosis following induction of dry eye in mice. Methods: Dry eye was induced in 3 groups of C57BL6 mice by subcutaneous injection of scopolamine TID and by exposure to an air draft and low humidity for 16 hours per day x 12 days. The control group (n=3) received no topical treatment, a second group (n = 3) received 1ul of 0.05% CSA topically TID, and the third group (n = 3) received 1ul of the castor oil vehicle of CSA topically TID. Three normal mice were used as untreated controls. After 12 days, the mice were sacrificed, and the eyes and ocular adnexa were excised, frozen, and cryosectioned. Additionally conjunctival and corneal samples were fixed in gluteraldehyde for transmission electron microscopy (TEM). Apoptosis was detected in frozen sections with the ApopTag® (ISOL) In Situ Oligo Ligation Kit that specifically detects DNA markers of apoptosis. Immunohistochemical staining for activated caspase-3 was performed to assay for this enzyme that is involved in the apoptotic cascade. Results: Compared to untreated controls and dry eye mice receiving CSA, the number of ISOL-positive epithelial cells in the bulbar and tarsal conjunctiva was significantly greater in the dry eye mice and dry eye mice receiving vehicle (P< 0.01 for both groups.) There was no significant difference in ISOL-positive conjunctival epithelial cells between the dry eye mice and dry eye mice receiving vehicle. Loss of goblet cells was observed in areas with the greatest density of ISOL-positive cells in these two groups. There was no significant difference in ISOL-positive cells in the corneal epithelium between groups. CSA treated dry eye mice showed less activated caspase-3 staining than the dry eye and dry eye + vehicle groups. TEM showed loss of superficial differentiated cells and extensive nuclear fragmentation characteristic of apoptosis in the dry eye and dry eye + vehicle groups, but not in the CSA group. Conclusions: Topical CSA significantly reduced conjunctival epithelial apoptosis and preserved goblet cells in experimental murine KCS. This may be a key mechanism for the therapeutic effect of CSA for KCS.
This PDF is available to Subscribers Only