Purchase this article with an account.
J Zhao, T Nagasaki, DM Maurice; Source of Mouse Tear Factors that Are Cytotoxic to Corneal Keratocytes . Invest. Ophthalmol. Vis. Sci. 2002;43(13):3132.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine the source of factors in the mouse tear fluid that are cytotoxic to the corneal keratocytes. Methods: The following biological tissues and fluids were examined as a potential source: extraorbital lacrimal gland (ELG), intraorbital lacrimal gland (ILG), Harderian gland, Meibomian gland, corneal epithelium, bulbar conjunctiva, palpebral conjunctiva, serum, aqueous humor, tears stimulated by pilocarpine, and stimulated lacrimal fluid collected from the secretory duct of ELG. These specimens were assayed either directly or after incubation at 37°C for 2-15 hours. Cytotoxicity against the keratocytes was assessed by an ex vivo assay using an isolated eye, in which central epithelium was removed from the cornea, test samples incubated on the surface of bare stroma, and loss of underlying keratocytes determined by fluorescently staining the remaining nuclei. In some animals, cytotoxicity of closed eye tears was examined in vivo after surgical removal of ELG. Results: The ex vivo experiments showed that ELG and ILG exhibited a strong cytotoxic effect that was comparable to the tears when assayed with or without preincubation. Lacrimal fluid collected from the ELG secretory duct was also effective, similar to the tear fluid collected from the eye surface. In addition, preparations of bulbar, but not palpebral, conjunctiva showed weak cytotoxicity after preincubation at 37°C for 8-15 hours, but it appeared to be different from the tear cytotoxicity as judged by the distinct courses of nuclear deterioration induced by these specimens. No other materials exhibited a cytotoxic effect. In the in vivo experiments, surgical removal of ELG prevented keratocyte loss under closed eyes after epithelial removal while the loss of keratocytes was obvious in the contralateral eye that received sham surgery. However, the tears regained the ability to trigger keratocyte loss gradually 4-24 hours after the surgery, suggesting that the loss of ELG may be compensated by ILG. Conclusion: ELG and ILG are the major source of the tear factors cytotoxic to the corneal keratocytes in the mouse. Cytotoxicity can also be detected in the bulbar, but not palpebral, conjunctiva after preincubation for 8-15 hours, but it appears to be distinct from the tear cytotoxicity.
This PDF is available to Subscribers Only