[Research on retinoic acid signals in retina of guinea pig eyes with different monochromatic illumination].
OBJECTIVE
Retinoic acid (RA) is the only extrinsic biochemical candidate that could act as a growth controller, the present study was designed to evaluate the retinoic acid signals in retina of guinea pig eyes with different monochromatic illumination.


METHODS
Ninety 2-week-old guinea pigs were divided into 3 groups randomly and were raised under green (530 nm) (n = 30), blue (430 nm) (n = 30) or white lighting (5000K) (n = 30) conditions. The axial length was measured with Cine scan A/B ultrasonography before, 2 weeks, 4 weeks, 8 weeks during experiment. After the biometrical measurement finished, 9 guinea pigs were sacrificed randomly in each group and retina was dissected. The RA level in retina was detected by High Performance Liquid Chromatography (HPLC). The expressions of retinoic acid-binding proteins I (CRABP-I) and retinoic acid receptor-β (RAR-β) protein and mRNA were assayed by Western-blot and Real-time PCR, respectively. The experiment and use of animals followed the Standard of Association for Research in Vision and Ophthalmology.


RESULTS
1. The axial length among the three groups showed a significant difference at 4 weeks during experiment (F = 3.946; P < 0.05), the green lighting group showed the fastest growing, the axial length of the three groups are (8.36 ± 0.11) mm (green), (7.88 ± 0.49) mm (blue), 7.98 ± 0.32 mm (white) respectively at 8 weeks during experiment; 2. The RA levels demonstrated a same trend with the axial length, at 8 weeks during experiment the RA levels are 4.846 ± 0.56 µg/g (green), 3.583 ± 0.26 µg/g (blue), 4.419 ± 0.36 µg/g (white) respectively; 3. Changes of the expression of CRABP-I and RAR-β occurred at different times, a significant difference of RAR-β among three groups appeared earlier, the green lighting group showed a highest level.


CONCLUSIONS
The different levels of retinoic acid signals were showed in retina of guinea pig eyes under different monochromatic illumination. The eye growth was significantly faster in green group than in blue group and white group, meanwhile, the RA level, the expressions of CRABP-I and RAR-β in the retina were higher in green group than the other two groups. These findings suggest that RA may act as a messenger in eye growth promoted by different monochromatic illumination.
Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai 200031, China.
Jia
J
Huang
Xiao-mei
XM
Qu
Ren-yuan
RY
Chu
D000818:Animals; D006168:Guinea Pigs; D008029:Lighting; D010775:Photic Stimulation; D012160:Retina / Q000378:metabolism* / Q000528:radiation effects*; D015398:Signal Transduction; D014212:Tretinoin / Q000378:metabolism*
D014212:Tretinoin