Abstract
Purpose:
Antioxidant supplements are supposed to decrease oxidative damage and prevent age-related ocular diseases. We previously reported the effects that antioxidant supplement containing lutein have on increasing the scavenging activity of superoxide and the amount of hydrogen peroxide in human aqueous humor. We also reported on the increased expression of anti-oxidative enzymes in the lenticular anterior capsule after antioxidant supplementation. Aquaporin 8 (AQP8) is known as a diffusion facilitator for transporting hydrogen peroxide through the cell membrane. It may be the key to disclosing the possible mechanism of increasing hydrogen peroxide in aqueous humor and the correlation to increasing anti-oxidative enzymes in the lenticular epithelium. In this study, the effects of antioxidant supplement on expression of AQP8 in the lenticular anterior capsule were measured. This is the first investigation of AQP8 in human cataractous lenses.
Methods:
13 male and 11 female patients with binocular cataract were included after giving their informed consent. Anterior capsules were sampled during cataract surgery (as pre-intake samples). Antioxidant supplement, Ocuvite+Lutein ® was orally taken from the following day. Six weeks later, anterior capsule was sampled during cataract surgery for the opposite eye (as post-intake samples). RNA was purified from homogenized samples and cDNA was reverse-transcribed for measuring of mRNA. Gene expression of APQ8 was measured using real time polymerase chain reaction. The statistical differences were analyzed using the chi-square test.
Results:
Among male patients, the gene expression rate of AQP8 significantly decreased after the supplementation (84.6% in pre-intake and 30.8% in post-intake samples, p<0.05). Among female patients, there were no statistical differences between pre- and post-intake samples. There were statistical differences between genders before supplementation (p<0.05), but no differences after the supplementation.
Conclusions:
Among male patients, decreasing expression rate of AQP8 is presumed to inhibit the influx of hydrogen peroxide into the lens epithelium after supplementation, whereas the rate of AQP8 gene expression remained the same after supplementation among female patients. Therefore, the antioxidant supplement may effect different mechanisms between genders.
Keywords: 424 antioxidants •
445 cataract •
533 gene/expression