Abstract
Purpose::
Since autologous serum is useful for the treatment of severe dry eye, serum components may be a potential candidate for the treatment of dry eye. We found selenoprotein P (SeP), which is a new candidate for the treatment of dry eye, from serum components. SeP contains 10 Selenocysteine (Sec) residues, which is essential amino acid of glutathione peroxidase (GPx) activity, and transport Sec to peripheral tissues. GPx catalyze hydorgen peroxide and lipid peroxides.
Methods::
Conjunctival epithelial cell line, CCL20.2 (CCL) requires 10% fetal bovine serum (FBS) in the medium to survive. When serum is removed from the culture medium, CCL undergo apoptosis. Human serum was fractionated by column chromatography. Each fraction was added to the medium in exchange for FBS to assay the ratio of apoptosis of the cells, which is an index of purification. Finally, since we identified SeP as a candidate, we tried to apply SeP to dry eye model rat. Dry eye model rat was prepared by removing both lacrimal glands from SD rat. To estimate a degree of dry eye condition, cornea of both eyes were stained with fluorescein, and stained-area was scored after 4 week’s treatment. Right eye of rat was treated with SeP and the other eye was treated with PBS.
Results::
Fluoescein score of PBS-treated cornea was 7.6 ± 3.6. Fluoescein score treated with SeP was significantly lowed (2.4 ± 2.2). Treatment with fragment of C-terminal of SeP, which contains 9 Sec residues, also suggest same effect as treatment with whole SeP. SeP treatment suppressed increment of fluorescein score induced by removing lacrimal glands, which may be involving in oxidative stress.
Conclusions::
It was suggested that SeP was a useful candidate for the treatment of dry eye.
Keywords: cornea: basic science • oxidation/oxidative or free radical damage • drug toxicity/drug effects