Abstract
Purpose::
Albino rats raised in bright cyclic light (400 lux) are protected against intense light-induced photoreceptor cell apoptosis, compared to animals raised in dim cyclic light (5 lux), suggesting a light adaptation phenomenon exists. To understand the molecular mechanism(s) underlying light adaptation phenomenon, retinal proteins induced by bright cyclic light rearing were identified by using a proteomic approach.
Methods::
Albino rats born in dim (5 lux) or bright (400 lux) cyclic (12 h/12 h on/off) light were raised in same cyclic light environment until they were 4 weeks old. Retinas were removed, pooled (6 retinas/sample), and subjected to 2-dimensional gel electrophoresis (2-DE). Proteins were identified by peptide mass fingerprinting.
Results::
In 3 independent sets of experiment, 6 protein spots were consistently increased in bright-reared samples compared to dim-reared samples. By mass spectrometry and peptide mass fingerprinting, 4 proteins including actin, ezrin, transferrin, and a member of protein disulfide isomerase were identified.
Conclusions::
Bright cyclic light-rearing up-regulates specific proteins in the rat retina. Increase of such proteins may be involved in the neuroprotective mechanism(s) of light adaptation phenomenon in rats.
Keywords: retina • proteomics • neuroprotection