中文摘要：

·AIM:All-trans retinoic acid (RA) is the only extrinsic biochemical candidate known to date that could act as a growth controller,the aim of this study was to investigate the expression cellular retinoic acid binding proteins I (CRABP-I) and retinoic acid receptor-β (RAR-β) in retina of the guinea pig eyes with experimental myopia.·METHODS:Ninety guinea pigs aged 14 days were equally and randomly divided into three groups:form deprivation (FD),-5D lens,and control.The diffusers for FD were white translucent hemispheres,and-5D lenses were used to introduce hyperopic defocus.Refraction was measured with streak retinoscopy after cycloplegia,and axial length was calculated with Cinescan A/B ultrasonography.Retina harvested at different time points were used to measure RA level with HPLC and expressions of cellular retinoic acid binding proteins I (CRABP-I) and RA receptor-β (RAR-β) were assayed with Western blot and Real-time PCR.SPSS13.0 software was used for statistical analysis.·RESULTS:Up-regulations of CRABP-I and RAR-β in ocular tissues correlated with changes in the refractive status and growth rate of the guinea pig eye (P 【0.05).14 days of monocular form-deprivation led to-5.14D myopia and a 0.281mm axial elongation;14 days of monocular defocus produced-3.64D myopia and a 0.163 mm axial elongation.The level of retinal RA started to elevate in 7 days (P 【0.05) after visual manipulation in both FD and-5D lens groups and became more prominent by 14 days (P 【0.01).The expressions of CRABP-I and RAR-β increased by 14 days after visual manipulation (P 【0.05),the mRNA level of RAR-β,however,increased by 7 days after visual manipulation (P 【0.05),which suggested that changes of expressions of CRABP-I and RAR-β might lag behind the change of RA.·CONCLUSION:The levels of CRABP-I and RAR-β were elevated in retina of the guinea pig eye with experimental myopia.During the progression of experimental myopia,the retinal RA level increased rapidly,and there might be a positive feedback between t