实验性近视眼视网膜多巴胺转运蛋白研究

目的　研究鸡眼视网膜多巴胺转运蛋白 (dopaminetransporter,DAT)的分布及其在实验性近视眼形成中的变化和可能作用。方法　孵化第 2d的 30只雏鸡随机分为Ⅰ～Ⅳ组 ,Ⅰ、Ⅱ及Ⅲ组小鸡单眼分别戴 - 10 0 0D、- 2 0 0 0D透镜及半透明眼罩 ,对侧眼为正常对照眼 ;Ⅳ组为正常对照组。3周后检测各组小鸡双眼屈光状态及眼轴长度。各组小鸡于一侧大腿肌注射1 2 5碘 2 β 甲氧羰基 3β (4 碘苯基 )托烷 ,2h后将其处死 ,摘出双眼球并解剖出全层视网膜组织 (Ⅰ和Ⅳ组 )或将视网膜神经上皮层与视网膜色素上皮层 (retinalpigmentepithelium ,RPE)分别取下 (Ⅱ和Ⅲ组 ) ,应用γ 计数器检测各组标本的DAT放射性计数 ,并进行比较。结果　Ⅱ组小鸡双眼的RPE组织标本的DAT放射性计数与视网膜神经上皮层比较 ,差异均有非常显著意义 (t=9 173,4 2 95 ;P <0 0 1) ;Ⅲ组小鸡双眼的RPE组织标本的DAT放射性计数与视网膜神经上皮层比较 ,差异均有非常显著意义 (t=13 84 8,9 6 74 ;P <0 0 1)。Ⅰ、Ⅱ及Ⅲ组全层视网膜组织标本或RPE组织标本的DAT放射性计数分别与对侧正常对照眼比较 ,差异均有非常显著意义 (t=5 5 85 ,4 92 3,5 791;P <0 0 1)。结论　鸡眼视网膜DAT主要分布在RPE。视网膜DAT可能参与小鸡形觉剥夺性近视

Studies of retinal dopamine transporter in experimental myopia

OBJECTIVE: To investigate the distribution of dopamine transporter (DAT) in the chicken eye and to explore the role of DAT in the occurrence of experimental myopia. METHODS: Thirty 2-day-old chickens were divided into four groups. Chicken eyes were fitted with lenses of -10 D (Group 1), -20 D (Group 2) and translucent goggles (Group 3) unilaterally. Chickens without any treatments were used as the control (Group 4). The refraction and the axial eye length of all chickens were measured after 3 weeks, then, all chickens were given an intramuscular injection of (125)I-beta-CIT 2beta-carbomethoxy-3beta-(4-iodophenyl) tropane] and sacrificed two hours after injection. Retinal pigment epithelium (RPE) and neural retina were dissected from the eye as a whole layer in Groups 1 and 4; and dissected separately in Groups 2 and 3. Radioactive DAT from each specimen was assayed by gamma-counter. RESULTS: In Groups 2 and 3, the radioactive DAT value in the RPE from the experimental eyes was significantly greater than that in the neural retina and also greater than those in the RPE from the control eyes (P < 0.01). In Groups 1, 2, and 3, the radioactive DAT value in the whole retina or RPE from the experimental eyes was significantly greater than those from the control eyes (P < 0.01). CONCLUSIONS: Retinal DAT is located mainly in the RPE and may be involved in the occurrence of both lens-induced myopia and form-deprivation myopia. These methods may provide a new approach for further studying the role of dopamine system in the occurrence of experimental myopia.