Cytoprotective effects of rebamipide and carteolol hydrochloride against ultraviolet B-induced corneal damage in mice.
OBJECTIVE
To analyze whether rebamipide (REB) and carteolol hydrochloride (CH) protect against UVB-induced corneal damage in mice.


METHODS
BALB/c mice topically pretreated with REB (1 and 10 mM) or CH (1, 10, and 100 mM) were exposed to ultraviolet (UV) B light at 416 micro W/cm(2). To evaluate corneal damage, mire irregularity was graded, and the haze index was estimated by using digitized corneal images. The formation of oxidized DNA in the corneal epithelium resulting from UVB exposure was estimated by using quantitative immunohistochemistry for 8-hydroxy-2-deoxyguanosine (8OHdG index). To analyze the mechanism of cytoprotection by REB and CH against UVB-induced cell damage, the UV absorption spectrum in these agents was evaluated by spectrophotometry, and their hydroxyl radical scavenging effect was evaluated by the electron spin resonance (ESR) spin trapping technique with Fenton system hydroxy radical generation.


RESULTS
Seventy-two hours after UVB exposure, the severity of mire irregularity, haze index, and 8OHdG index were significantly lower in mice pretreated with 10 mM (P < 0.05, P < 0.05, and P < 0.01, respectively) of REB and in mice pretreated with 10 mM (P < 0.05, P < 0.01, and P < 0.01, respectively) and 100 mM (P < 0.01, P < 0.01, and P < 0.01, respectively) of CH compared with mice treated with vehicle. The absorption spectrum of REB overlapped with the UVB wavelength, and that of CH overlapped partially. The ESR spin signal corresponding to the hydroxyl radical was reduced by the addition of REB or CH.


CONCLUSIONS
REB and CH attenuate UVB-induced corneal damage, which may be partly responsible for their sunscreening and hydroxyl radical scavenging effects.
Tanito
Masaki
M
Department of Ophthalmology, Shimane Medical University, Izumo, Shimane, Japan.
Takanashi
Taiji
T
Kaidzu
Sachiko
S
Yoshida
Yasukazu
Y
Ohira
Akihiro
A
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000409:Alanine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D000818:Animals; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D002354:Carteolol / Q000627:therapeutic use*; D003315:Cornea / Q000528:radiation effects*; D003316:Corneal Diseases / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D019610:Cytoprotection; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D015363:Quinolones / Q000627:therapeutic use*; D011833:Radiation Injuries, Experimental / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D014466:Ultraviolet Rays
D000319:Adrenergic beta-Antagonists; D000897:Anti-Ulcer Agents; D015363:Quinolones; D000080242:8-Hydroxy-2'-Deoxyguanosine; D002354:Carteolol; D003849:Deoxyguanosine; C052785:rebamipide; D000409:Alanine