Comprehensive evaluation of the extraocular muscle critical period by expression profiling in the dark-reared rat and monocularly deprived monkey.
OBJECTIVE
To address the consequences of visual deprivation paradigms in rat (dark rearing) and monkey (monocular deprivation) on extraocular muscle (EOM) development using genome-wide expression profiling.


METHODS
Serial analysis of gene expression (SAGE) was used to determine alterations in the EOM transcriptome induced by dark rearing of rats from birth to postnatal day 45. Data were compared with previously published normal EOM SAGE library. DNA microarray similarly assessed changes in gene expression patterns of EOMs of monkeys reared from birth to 4 months of age with monocular deprivation.


RESULTS
Dark rearing produced changes in expression of 280 transcripts in rat EOM. Of these, 71 were known genes representing functional categories that included energy metabolism/mitochondrial-related (21%), protein synthesis and modification (14%), lipid metabolism (13%), and muscle-related (6%) transcripts. Together, the predominant pattern reflected an energetic shift toward fatty acid beta-oxidation and integrated alterations in both myofibers and supportive tissues. The response of monkey rectus muscles to monocular deprivation was considerably less severe.


CONCLUSIONS
The visual deprivation paradigms used in this study mimic alterations that are associated with the common disorders of strabismus, congenital cataract, and amblyopia. These data show that postnatal EOM maturation is broadly susceptible to changes in activity patterns that are a consequence of visuomotor maldevelopment. The data extend the concept of an EOM-critical period and establish that activity patterns in developing eye movement systems play vital determinant roles in the novel EOM phenotype.
Cheng
Georgiana
G
Department of Ophthalmology, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, Ohio 44106, USA.
Mustari
Michael J
MJ
Khanna
Sangeeta
S
Porter
John D
JD
D000818:Animals; D003623:Dark Adaptation / Q000502:physiology*; D020224:Expressed Sequence Tags; D005136:Eye Proteins / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D008253:Macaca mulatta; D008297:Male; D009124:Muscle Proteins / Q000235:genetics; D009801:Oculomotor Muscles / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012683:Sensory Deprivation / Q000502:physiology*
D005136:Eye Proteins; D009124:Muscle Proteins