豚鼠形觉剥夺性近视视网膜中视黄酸转运系统的研究

目的了解视黄醇（RA）转运系统在豚鼠近视发生发展中的作用。方法2周龄英国短毛豚鼠48只,随机分为形觉剥夺组（n=24）和正常对照组（n=24）。形觉剥夺组随机取1只眼,用白色半透明眼罩遮盖形成形觉剥夺,遮盖时间为2周,干预前后均采用睫状肌麻痹后带状光检影法测定其屈光不正状态,用CinescanA/B型超声仪测定玻璃体腔深度和眼轴长度。处死后取视网膜,用HPLC法测定视网膜中的RA水平,Westernblot法定量检测视网膜中视黄酸结合蛋白-Ⅰ（CRABP-Ⅰ）和视黄酸核受体-β（RAR-β）的蛋白水平,并用Real-timePCR法测定其mRNA水平。结果形觉剥夺后模型眼的等效球镜为（-3.82±0.13）D,对照眼为（1.99±0.58）D,差异有统计学意义（t=8.376,P〈0.01）;形觉剥夺组眼轴长度为（8.346±0.047）mm,对照组眼轴长度为（7.888±0.042）mm,差异有统计学意义（t=3.343,P〈0.05）。形觉剥夺组视网膜RA水平较对照组高,差异有统计学意义（t=4.934,P〈0.01）;模型眼视网膜中CRABP-Ⅰ和RAR-β的含量较对照组均提高（P〈0.05）。结论豚鼠形觉剥夺性近视眼视网膜中RA转运系统水平显著上升,RA可能是近视发展的信使。

Research on retinoic acid system in retina of guinea pig eyes with form deprivation myopia

Objective Development of eyeball is visually regulated by messengers that released from the retina, and research demonstrated that retinoic acid (RA) is the only extrinsic biochemical candidate that could act as a growth controller. Present study was designed to evaluate the RA system in retina of guinea pig eye with experimental form deprivation myopia. Methods The form deprivation myopia models were monocularly established in the 24 2-week-old guinea pigs by occluding the lateral eyes using white translucent hemispheres for two weeks, and the fellow eyes were as normal control. Refraction diopter was detected with streak retinoscopy after cycloplegia, and axial length and vitreous depth were calculated with Cinescan A/B ultrasonography before and 2 weeks after experiment. All animals were sacrificed and retina was dissected 2 weeks after experiment. The RA level in retina was delected by High Performance Liquid Chromatography (HPLC). The expressions of RA-binding proteins Ⅰ(CRABP-Ⅰ) and RA receptor-β(RAR-β) protein and mRNA were assayed by Western-blotting and Real-time PCR, respectively. The experiment and use of animals followed the Standard of Association for Research in Vision and Ophthalmology. Results The spherical equivalent refraction was (+ 3. 00 ± 0. 75) D in the model group and (+ 2. 88 ± 0. 67) D in control eyes (t= 0. 672, P ＞ 0. 05), the ocular axial length was (7. 822 ± 0. 083) mm in model group and (7. 791 ±0.073) mm in control eyes before experiment (t = 0. 346, P ＞ 0. 05). In 2 weeks after experiment, the spherical equivalent refraction was (- 3. 82 ± 0. 13) D versus (1. 99 ± 0. 58) D and axial length was (8. 346 ± 0. 047) mm versus (7. 888 ± 0. 042) mm between model eyes and control eyes (t = 8. 376, P ＜ 0. 001; t = 3. 343, P ＜0. 05). No significant difference in the level of RA in retina before and after experiment (1. 394 ±0. 079 μg/g vs 1. 295 ±0. 023 μg/g) (t =0. 897, P ＞0. 05) but obviously elevated after experiment in model eyes compared with control eyes (2. 356 ± 0.098 μg/g vs 1.499 ±0.035 μg/g) (t =4. 934, P ＜0. 01). The expression of CRABP-Ⅰ and RAR-β mirrored these directional changes. Conclusion The RA system in retina is upregulated in the eye of guinea pig with form deprivation myopia. This findings suggests that RA may act as a messenger in the development of experimental myopia.