Prolonged rhodopsin phosphorylation in light-induced retinal degeneration in rat models
Prolonged rhodopsin phosphorylation in light-induced retinal degeneration in rat models
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DOI：
10.1167/iovs.05-1149
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发表时间：
2006-12-01
影响因子：
4.4
通讯作者：
Nakazawa, Mitsuru
中科院分区：
文献类型：
--
作者：
Ishikawa, Futoshi;Ohguro, Hiroshi;Nakazawa, Mitsuru
目的.在视网膜变性大鼠模型上观察各种光诱导应力对视网膜的影响。视网膜形态学和视网膜电图（ERG）进行了分析后，应用光诱导应力的几个强度（650，1300，2500，或5000勒克斯）。为了评价视紫红质（Rho）的功能，Rho再生和去磷酸化的动力学进行了研究，通过分光光度分析和免疫荧光标记的抗体特异性针对磷酸化残基334 Ser和338 Ser在C末端的Rho。用ELISA法测定视网膜cGMP浓度。通过RT-PCR定量评价神经营养因子（FGF 2、脑源性神经营养因子[BDNF]、血小板源性生长因子[PDGF]和睫状神经营养因子[CNTF]）的表达水平。在野生型和皇家外科学院（RCS）大鼠视网膜中观察到ERG反应的光强度依赖性恶化和视网膜外核层变薄。在光诱导应激后的暗适应下，野生型和RCS大鼠视网膜之间的Rho再生动力学没有差异。与没有光诱导应激的野生型相比，RCS大鼠视网膜中334 Ser和338 Ser处的Rho去磷酸化极其延迟，但RCS和野生型大鼠视网膜中这些位点处的Rho去磷酸化变得更慢。在神经营养因子的表达方面，在光诱导应激后的动物之间几乎没有观察到显著的变化。本研究表明，光诱导的应激导致野生型和RCS大鼠视网膜中视网膜功能和形态的强度依赖性恶化。Rho去磷酸化的较慢动力学导致的光转导级联的破坏似乎参与视网膜变性。
PURPOSE. The effects of various light-induced stresses on the retina were examined in the retinal degenerative rat model.METHODS. Retinal morphology and electroretinograms (ERGs) were analyzed after application of light-induced stress of several intensities (650, 1300, 2500, or 5000 lux). For evaluation of rhodopsin (Rho) function, the kinetics of Rho regeneration and dephosphorylation were studied by spectrophotometric analysis and immunofluorescence labeling with antibodies specifically directed toward the phosphorylated residues 334Ser and 338Ser in the C terminus of Rho. Retinal cGMP concentration was determined by ELISA. Expression levels of neurotrophic factors (FGF2, brain-derived neurotrophic factor [BDNF], platelet-derived growth factor [PDGF], and ciliary neurotrophic factor [CNTF]) were evaluated quantitatively by RT-PCR.RESULTS. Light intensity-dependent deterioration of ERG responses and thinning of the retinal outer nuclear layer were observed in wild- type and Royal College of Surgeons (RCS) rat retinas. Under dark adaptation after light-induced stress, the kinetics of Rho regeneration were not different between wildtype and RCS rat retinas. Rho dephosphorylation at 334Ser and 338Ser was extremely delayed in RCS rat retinas compared with wild- type without light-induced stress, but Rho dephosphorylation at those sites became slower in both RCS and wild- type rat retinas. In terms of expression of neurotrophic factors, almost no significant changes were observed between the animals after light-induced stress.CONCLUSIONS. The present study indicates that light-induced stress causes intensity-dependent deterioration in retinal function and morphology in wild- type and RCS rat retinas. Disruption of the phototransduction cascade resulting from slower kinetics of Rho dephosphorylation appears to be involved in retinal degeneration.