Abstract
Purpose: :
Glutathione (GSH) is known to constitute the first line of the cellular defense against oxidative injury. Oxidative stress and/or cell-viability decline results in the reduction of intracellular glutathione contents (icGSH) of the cells. To investigate the severity of dry eye, and to verify the effects of punctual occlusion (PO) on the fluctuation of icGSH content was investigated.
Methods: :
Conjunctival surface cells were collected by the impression cytology technique. Enrolled dry eyes were categorized into 3 groups: aqueous tear-deficient dry eye [ATDDE, diagnosis based on an abnormal Schirmer 1 test value (ST1; ≤ 5mm/5min) and abnormal score of ocular surface staining (≥3, scores from 0 (none) to 9 (the severest)] with Sjögren’s syndrome (SSDE; diagnosis based on the Fox’s criteria) (SSDE: n=40); without SS (non-SSDE group) (n=40); short-BUT type dry eye (SBUT, characterized by the abnormal fluorescein breakup time (F-BUT) ≤ 5sec with no abnormal ST1 and no abnormal staining) (n=40); and age matched controls (n=40), and the findings from those groups were then evaluated. Nitrocellulose filters were directly stained with monochlorobimane and evaluated under a confocal laser scanning microscope.
Results: :
More icGSH existed in the cytoplasm than in the nucleus. The icGSH level of the elderly normal volunteers (n=40, mean age: 80±1.9 years) was significantly reduced (9%) compared with the young normal volunteers (n=40, mean age: 24±0.4 years) (p<0.01). The icGSH level was significantly reduced in SBUT (28%), non-SSDE (64%), and SSDE (79%) in comparison with age-matched normal controls, respectively (p<0.001). Except in SSDE, the secondary layer of conjunctiva showed a normal icGSH level, and the icGSH level of the superficial layer was recovered after the PO. However, icGSH of SSDE conjunctival cells never recovered after PO although corneal keratitis did recover.
Conclusions: :
This study presents a new icGSH evaluation system for effectively evaluating ocular surface inflammation. GSH and its related oxidative mechanism may be involved in underlying mechanism of dry eye. Specifically, immunological inflammation, as well as aqueous tear deficiency at the conjunctival area are present in cases of SSDE.
Clinical Trial: :
http://www.clinicaltrials.gov NCT00718926
Keywords: cornea: tears/tear film/dry eye • imaging/image analysis: clinical • cornea: basic science