School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, State Key Laboratory of Optometry, Ophthalmology, and Vision Science, Wenzhou, Zhejiang, China.
Invest Ophthalmol Vis Sci. 2018 Sep 4;59(11):4631-4638. doi: 10.1167/iovs.17-22315.
To determine if myopia in albino guinea pigs is linked to altered ocular dopamine (DA) levels in both the retinal and uveal dopaminergic systems.
Retina and retinal pigment epithelium (RPE)/choroid were dissected from eyes of 2-week-old albino myopic (AM) and pigmented hyperopic (PH) guinea pigs. The levels of DA, dihydroxy-phenyl acetic acid (DOPAC), and homovanillic acid (HVA) were determined. Tyrosine hydroxylase (TH) and tyrosinase activities were also measured. PH animals received daily unilateral peribulbar injections of either kojic acid (tyrosinase inhibitor) or vehicle for 2 to 4 weeks. Refractive errors and ocular axial dimensions were measured by eccentric infrared photoretinoscopy and A-scan ultrasonography.
Retinal DA levels were similar between the two strains, but AM eyes had higher levels of DOPAC. RPE/choroid DA and tyrosinase activity in AM eyes were lower than in PH eyes (P < 0.01); however, the DA turnover was higher (P < 0.05). After 2 weeks of kojic acid treatment, PH eyes developed significant myopia, accompanied by elongated vitreous chambers and axial lengths. Inhibition of tyrosinase activity was linearly correlated with a myopic refraction shift (R = 0.79, P < 0.01). PH animals that received 62.5 ng/mL kojic acid treatment daily for 2 weeks followed by 625 ng/mL for 2 more weeks became more myopic and had deeper anterior chambers compared to those that received the 62.5 ng/mL dose over this period (P = 0.04).
The uveal tyrosinase-dependent dopaminergic system is involved in the development of guinea pig refraction. Enhancing uveal tyrosinase activity might slow down the development of myopia.
确定白化豚鼠的近视是否与视网膜和葡萄膜多巴胺能系统中多巴胺（DA）水平的改变有关。
从 2 周龄白化性近视（AM）和色素性远视（PH）豚鼠的眼睛中分离视网膜和视网膜色素上皮（RPE）/脉络膜。测定 DA、二羟苯乙酸（DOPAC）和高香草酸（HVA）的水平。还测量了酪氨酸羟化酶（TH）和酪氨酸酶的活性。PH 动物每天接受单侧眶周注射曲酸（酪氨酸酶抑制剂）或载体 2 至 4 周。通过偏心红外视网膜摄影术和 A 型超声扫描测量屈光不正和眼轴尺寸。
两种品系的视网膜 DA 水平相似，但 AM 眼的 DOPAC 水平较高。AM 眼的 RPE/脉络膜 DA 和酪氨酸酶活性低于 PH 眼（P<0.01）；然而，DA 周转率更高（P<0.05）。曲酸治疗 2 周后，PH 眼发生明显近视，伴有玻璃体腔拉长和眼轴长度增加。酪氨酸酶活性的抑制与近视折射变化呈线性相关（R=0.79，P<0.01）。每天接受 62.5 ng/ml 曲酸治疗 2 周，然后再接受 625 ng/ml 治疗 2 周的 PH 动物比接受 62.5 ng/ml 剂量治疗的动物更近视，前房更深（P=0.04）。
葡萄膜酪氨酸酶依赖性多巴胺能系统参与豚鼠屈光度的发育。增强葡萄膜酪氨酸酶活性可能会减缓近视的发展。
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