Fujikado T, Tsujikawa K, Tamura M, Hosohata J, Kawasaki Y, Tano Y
Department of Applied Medical Engineering, Osaka University Graduate School of Medicine, Osaka, Japan.
Ophthalmic Res. 2001 Mar-Apr;33(2):75-9. doi: 10.1159/000055647.
It has still not been determined whether the retinal mechanism causing form-deprivation myopia (FDM) is different from that causing lens-induced myopia (LIM). We previously reported that FDM was blocked by an intravitreal injection of the nitric oxide (NO) synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME). In this study, we investigated the effect of L-NAME on LIM in chicks.
The left eyes of 6-day-old chicks were injected with 30 microl of nontoxic concentrations of L-NAME (< or = 360 mM) or saline. The right eyes were injected with 30 microl of saline. A -16 dpt lens was placed in front of the left eye for 6 days. Another group of 6 chicks were injected with 180 mM L-NAME (left eye) and with saline (right eye) before placing -16 dpt lenses in front of both eyes. After removing the lens, the refraction and the axial length were measured. The effect of L-NAME (180 mM) on the retina of a separate group of chicks was examined by electroretinography 60 min after an intravitreal injection in non-LIM-treated eyes.
The eyes of chicks that were injected with 180 or 360 mM L-NAME were less myopic and had significantly shorter axial lengths than control eyes. A significant decrease of the On response and an increase of the Off response were observed.
The injection of L-NAME into developing chick eyes that were then covered with a -16 dpt lens resulted in a modifications of retinal function and an inhibition of the development of myopia. These results, combined with the earlier findings, suggest that NO modulates a common retinal pathway that leads to both LIM and FDM.
导致形觉剥夺性近视（FDM）的视网膜机制是否与导致晶状体诱导性近视（LIM）的机制不同，目前仍未确定。我们之前报道，玻璃体内注射一氧化氮（NO）合酶抑制剂N-硝基-L-精氨酸甲酯（L-NAME）可阻止FDM。在本研究中，我们调查了L-NAME对雏鸡LIM的影响。
给6日龄雏鸡的左眼注射30微升无毒浓度的L-NAME（≤360 mM）或生理盐水。右眼注射30微升生理盐水。将-16日龄的晶状体置于左眼眼前6天。另一组6只雏鸡在双眼眼前放置-16日龄晶状体之前，左眼注射180 mM L-NAME，右眼注射生理盐水。移除晶状体后，测量屈光和眼轴长度。在未进行LIM处理的眼中玻璃体内注射60分钟后，通过视网膜电图检查L-NAME（180 mM）对另一组雏鸡视网膜的影响。
注射180或360 mM L-NAME的雏鸡眼睛近视程度较轻，眼轴长度明显短于对照眼。观察到开反应显著降低，关反应增加。
向发育中的雏鸡眼睛注射L-NAME，随后覆盖-16日龄晶状体，导致视网膜功能改变并抑制近视发展。这些结果与早期发现相结合，表明NO调节导致LIM和FDM的共同视网膜通路。
