Expression of SIRT1 and oxidative stress in diabetic dry eye.
OBJECTIVE
To explore the expression of SIRT1 with oxidative stress and observe physiological and pathological changes in the corneas as well as the association between SIRT1 and oxidative stress of diabetic dry eyes in mice.


METHODS
Forty-eight C57BL/6Jdb/db mice at eight weeks of age were divided randomly into two groups: the diabetic dry eye group and the diabetic group. An additional forty-eight C57BL/6J mice at eight weeks of age were divided randomly into two groups: the dry eye group and the control group. Every mouse in the dry eye groups (diabetic and normal) was injected with scopolamine hydrobromide three times daily, combined with low humidity to establish a dry eye model. After the intervention, phenol red cotton string tests and corneal fluorescein staining were performed. In addition, HE staining and immunofluorescence were done. Expression of SIRT1 in the cornea was examined by real-time PCR and Western Blot and expression of FOXO3 and MnSOD proteins was detected by Western Blot.


RESULTS
At one, four, and eight weeks post intervention, all of the groups except the controls showed significant decreases in tear production and increases in the corneal fluorescein stain (P<0.05 vs control). Between the experimental groups, the diabetic dry eye group had the least tear production and the highest corneal fluorescein stain score (P<0.05). As the disease progressed, all of the experimental groups showed obviously pathological changes in HE staining, particularly the diabetic dry eye group. In the 1(st) and 4(th) week, the expression of SIRT1, FOXO3, and MnSOD were significantly higher in the diabetic DE and DM groups but lower in the DE group compared to the controls (P<0.05). In the 8(th) week, the expression of SIRT1, FOXO3, and MnSOD was significantly down-regulated in the diabetic DE group and the DM group (P<0.05). Immunofluorescence showed similar results.


CONCLUSIONS
In the condition of diabetic dry eye, tear production declined markedly coupled with seriously wounded corneal epithelium. Oxidative stress in the cornea was enhanced significantly and the expression of SIRT1 was decreased.
Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine Shanghai 200090, China ; Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Hao
H
Liu
Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine Shanghai 200090, China ; Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Minjie
M
Sheng
Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine Shanghai 200090, China.
Yu
Y
Liu
Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Peng
P
Wang
Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Yihui
Y
Chen
Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Li
L
Chen
Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Weifang
W
Wang
Department of Ophthalmology, Yangpu Hospital, Tongji University School of Medicine Shanghai 200090, China ; Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University Shanghai 200072, China.
Bing
B
Li
D000818:Animals; D015153:Blotting, Western; D003315:Cornea / Q000201:enzymology* / Q000473:pathology; D048909:Diabetes Complications / Q000139:chemically induced / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D005455:Fluorescent Antibody Technique; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018384:Oxidative Stress; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012601:Scopolamine; D056564:Sirtuin 1 / Q000235:genetics / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D013666:Tears / Q000378:metabolism; D013997:Time Factors; D014985:Xerophthalmia / Q000139:chemically induced / Q000201:enzymology* / Q000235:genetics / Q000473:pathology
D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; C474033:FoxO3 protein, mouse; D012601:Scopolamine; D013482:Superoxide Dismutase; C470545:Sirt1 protein, mouse; D056564:Sirtuin 1
Dry eye; FOXO3; MnSOD; SIRT1; cornea; diabetes mellitus