Open AccessInduction of heme oxygenase 1 in the retina by intense visible light: suppression by the antioxidant dimethylthiourea.
Author(s) -
R. Krishnan Kutty,
Geetha Kutty,
Barbara Wiggert,
Gerald J. Chader,
Ruth M. Darrow,
D.T. Organisciak
Publication year - 1995
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.92.4.1177
Subject(s) - heme oxygenase , retina , messenger rna , oxidative stress , heme , biology , gene expression , oxygenase , microbiology and biotechnology , antioxidant , chemistry , endocrinology , biochemistry , gene , enzyme , neuroscience
The effect of intense visible light (light damage) on the expression of heme oxygenase 1 (HO-1), a protein induced by oxidative stress, was investigated in the rat retina. A sensitive reverse transcription-PCR assay demonstrated the expression of mRNA for HO-1 as well as HO-2, the noninducible HO form, in the normal retina. As analyzed by Northern blotting, however, HO-1 mRNA was barely detectable under normal circumstances. After exposure to intense visible light, retinas had markedly higher HO-1 mRNA levels than unexposed controls, with increases up to 52- and 98-fold at 12 and 24 hr of exposure, respectively. Intense light exposure also resulted in an increase in HO-1 protein. In contrast, no appreciable change in HO-2 mRNA or protein was observed. The increase in HO-1 message was more pronounced in rats previously reared in the dark than in those reared in a weak cyclic-light environment. A marked decrease from the high level of HO-1 mRNA induced by light insult was observed when the animals were allowed to recover in the dark for 24 hr after light exposure. Most important, treatment of animals with 1,3-dimethylthiourea, a synthetic antioxidant, prior to light exposure effectively blocked the increase in HO-1 mRNA. Thus, HO-1 is a sensitive marker for assessing light-induced insult in the retina. Since increased expression of HO-1 is thought to be a cellular defense against oxidative damage, its expression may play an important role in protecting the retina against light damage.