Melatonin reduces oxidative stress in the rat lens due to radiation-induced oxidative injury.
OBJECTIVE
The aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced cataract in the rat lens after total cranial irradiation with a single 5 Gray (Gy) dose of gamma irradiation.


METHODS
Twenty-eight Sprague-Dawley rats were used for the experiment.The rats were randomly divided into four equal groups. The control group did not receive melatonin or irradiation but received both 0.1 ml physiological saline intraperitoneally and sham irradiation. The irradiation (IR) group received 5 Gy gamma irradiation to the total cranium as a single dose plus 0.1 ml physiological saline intraperitoneally. The melatonin plus IR group received irradiation to the total cranium plus 5 mg/kg/day melatonin intraperitoneally. The melatonin group received only 5 mg/kg/day melatonin plus sham-irradiation. Biochemical parameters measured in murine lenses were carried out using spectrophotometric techniques.


RESULTS
Lens antioxidant capacity, as measured by levels of total superoxide scavenger activity (TSSA), non-enzymatic superoxide scavenger activity (NSSA) and glutathione reductase (GRD) activity, significantly increased in melatonin, control and melatonin plus IR groups when compared with the IR group. Lens glutathione-S-transferase (GST) activity significantly increased in control and melatonin groups when compared with the IR group. Lens malondialdehyde (MDA) levels significantly increased in the IR group when compared with control, melatonin and melatonin plus IR groups. Lens TSSA and NSSA activities significantly decreased in control and melatonin plus IR groups when compared with the melatonin group. Lens GST activity significantly increased in the control group when compared with melatonin plus IR group. Lens GRD activity significantly increased in melatonin and melatonin plus IR groups when compared with control group.


CONCLUSIONS
Melatonin reduces oxidative stress markers and augments anti-oxidant capacity in the rat lens.
Taysi
Seyithan
S
Department of Biochemistry and Clinical Biochemistry, Gaziantep University, School of Medicine, Gaziantep, Turkey. seytaysi@hotmail.com
Memisogullari
Ramazan
R
Koc
Mehmet
M
Yazici
Ahmet Taylan
AT
Aslankurt
Murat
M
Gumustekin
Kenan
K
Al
Behcet
B
Ozabacigil
Fatma
F
Yilmaz
Adnan
A
Tahsin Ozder
Hasan
H
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D004781:Environmental Exposure; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007908:Lens, Crystalline / Q000187:drug effects* / Q000378:metabolism* / Q000528:radiation effects; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D012886:Skull / Q000528:radiation effects; D013481:Superoxides / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
D000975:Antioxidants; D013481:Superoxides; D014969:Xanthine Oxidase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D008550:Melatonin