In the presence of ferritin, visible light induces lipid peroxidation of the porcine photoreceptor outer segment.
We studied the synergistic effect of visible light and ferritin on the lipid peroxidation on a fraction of porcine photoreceptor outer segment (POS). Reaction mixtures containing the POS fraction and horse spleen ferritin were irradiated under white fluorescent light mainly at 17,000 lx or incubated under dark conditions at 37 degrees C. The lipid peroxidation was evaluated by both the thiobarbituric acid method and the ferrous oxidation/xylenol orange method. The irradiation-induced lipid peroxidation was affected by some experimental factors such as the irradiation dose and acidity of the material. When the irradiation was stopped, the lipid peroxidation was also stopped; thereafter, the re-irradiation induced lipid peroxidation. Moreover, this lipid peroxidation was inhibited by desferrioxamine, an iron chelator, or by dimethylthiourea, a hydroxyl radical scavenger, suggesting that the lipid peroxidation involves hydroxyl radicals generated via the Fenton reaction by iron ion released from ferritin. The lipid peroxidation did not take place under dark conditions or in the absence of ferritin. This study suggested the possibility that the visible light-induced lipid peroxidation of the POS fraction in the presence of ferritin may participate in the etiology of human retinal degenerative diseases as the human retina is exposed to light for life.
Ohishi
Kentaro
K
Photon Medical Research Center, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan.
Zhang
Xiao Mei
XM
Moriwaki
Shinichi
S
Hiramitsu
Tadahisa
T
Matsugo
Seiichi
S
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D005293:Ferritins / Q000737:chemistry / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D008027:Light; D015227:Lipid Peroxidation; D008956:Models, Chemical; D010786:Photoreceptor Cells / Q000378:metabolism; D012160:Retina / Q000378:metabolism; D012374:Rod Cell Outer Segment / Q000737:chemistry* / Q000378:metabolism*; D019097:Spin Trapping; D013552:Swine; D013997:Time Factors
D000975:Antioxidants; D017665:Hydroxyl Radical; D005293:Ferritins; D006861:Hydrogen Peroxide