Effect of 5-S-GAD on UV-B-induced cataracts in rats.
OBJECTIVE
5-S-Glutathionyl-N-beta-alanyl-3,4-dihydroxyphenylalanine (5-S-GAD) is a novel antibacterial substance purified from Sarcophaga peregrina (flesh fly) that has both a radical scavenging activity and antioxidative activity. This is a report of an investigation of the effect of 5-S-GAD (eyedrops) on UVB-induced cataracts in rats.


METHODS
Brown Norway male rats (n = 32; 7 weeks old) were treated with either 5-S-GAD 0.1%, 5-SGAD 1%, astaxanthin (AST) 0.1% suspension eyedrops or the vehicle alone (the solution without 5-S-GAD) three times a day (three doses at 5-min intervals each time). The treatment was scheduled 2 days before UV-B exposure and 2 days after UV-B exposure. Exposure to 100-200 mJ/cm(2) UV-B was performed once a week between drug treatments for 9 consecutive weeks, with a total dose of 1200 mJ/cm(2) UV-B. Ocular penetration of 5-S-GAD was analyzed using high-pressure liquid chromatography (HPLC). Cataract formation was documented by an anterior eye segment analysis system once a week under mydriasis. The light-scattering intensity (LSI) of the anterior superficial cortex region was measured.


RESULTS
In the eighth to ninth week after the start of UV-B exposure, the LSI of anterior subcapsular lenses of 5-S-GAD-treated groups, as detected by HPLC, was significantly lower (P < 0.05) than that of the control, whereas no such difference was found in the AST-treated group.


CONCLUSIONS
5-S-GAD eyedrop application may delay the progression of UV-B-induced cataract in rats.
Department of Ophthalmology, Kanazawa Medical University, Ishikawa, Japan. hkawada@unmc.edu
Hiroyoshi
H
Kawada
Masami
M
Kojima
Takahito
T
Kimura
Shunji
S
Natori
Kazuyuki
K
Sasaki
Hiroshi
H
Sasaki
D000287:Administration, Topical; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002386:Cataract / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D002851:Chromatography, High Pressure Liquid; D004295:Dihydroxyphenylalanine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D004195:Disease Models, Animal; D016166:Free Radical Scavengers / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005978:Glutathione / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D007908:Lens, Crystalline / Q000503:physiopathology / Q000528:radiation effects*; D008027:Light; D008297:Male; D009883:Ophthalmic Solutions; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011833:Radiation Injuries, Experimental / Q000188:drug therapy* / Q000209:etiology; D051381:Rats; D011914:Rats, Inbred BN; D012542:Scattering, Radiation; D014466:Ultraviolet Rays / Q000009:adverse effects*
D000975:Antioxidants; D016166:Free Radical Scavengers; C100496:N-beta-alanyl-5-S-glutathionyl-3,4-dihydroxyphenylalanine; D009883:Ophthalmic Solutions; D004295:Dihydroxyphenylalanine; D011505:Protein-Tyrosine Kinases; D005978:Glutathione