Photic injury triggers apoptosis of photoreceptor cells.
Photic injury triggers apoptosis of photoreceptor cells.
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发表时间：
1996-05
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通讯作者：
A. Abler;Cheng‐Jong Chang;J. Ful;M. Tso;T. Lam
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作者：
A. Abler;Cheng‐Jong Chang;J. Ful;M. Tso;T. Lam
细胞凋亡是一种高度调控且依赖于能量的细胞死亡过程，在正常组织发育中发挥着重要作用。它在病理条件下的作用可能有所不同。早期的形态学研究表明细胞凋亡可能是光诱导的光感受器变性的重要机制。在这项研究中，我们确定了光暴露是否会在已建立的光感受器变性模型中触发光感受器细胞凋亡。将 28 只 Lewis 白化病大鼠分为七组，每组 4 只：一组作为未暴露的对照；一组作为对照组。其余组分别连续暴露于绿色荧光灯（320英尺烛光）下3、6、9、12、18或24小时，处死进行组织病理学检查、生化分离视网膜DNA。以及通过末端转移酶生物素-dUTP 缺口末端标记 (TUNEL) 对带缺口的核 DNA 进行原位分析。组织病理学研究揭示了与之前关于光损伤的报道相当的形态学变化。 DNA 的电泳分析显示，早在光照 12 小时时，核小体间 DNA 就发生裂解。 DNA片段（180-200个碱基对的单体和多聚体）的荧光强度随着光照时间的延长而增强。 TUNEL 技术早在光照 6 小时就将 DNA 裂解定位于感光细胞核，结果表明，TUNEL 阳性细胞核的数量随着光照的增加而增加，并揭示了上象限中更多的 DNA 降解。我们的研究结果证实了早期的形态学观察，即光暴露会引发感光细胞凋亡。
Apoptosis, a highly regulated and energy-dependent process of cell death, plays an important part in normal tissue development. Its role in pathological conditions may vary. Earlier morphologic studies suggest that apoptosis may be an important mechanism in light-induced photoreceptor degeneration. In this study, we determined if photic exposure triggers apoptosis in photoreceptor cells in an established model of photoreceptor degeneration by light exposure. Twenty eight Lewis albino rats were divided into seven groups of 4 animals each: one group served as the unexposed control; and the other groups were exposed continuously to green fluorescent light (320 foot-candles) for 3, 6, 9, 12, 18 or 24 hours, respectively and killed for histopathological examination, biochemical isolation of retinal DNA; and in situ analysis of nicked nuclear DNA by terminal transferase biotin-dUTP nick end labeling (TUNEL). Histopathological study revealed morphological changes comparable to previous reports on photic injury. Electrophoretic analysis of DNA showed internucleosomal DNA cleavage as early as 12 hours of light exposure. The fluorescent intensity of DNA fragments, which were monomers and multimers of 180-200 base pairs, increased with the duration of light exposure. TUNEL technique, which localized DNA cleavage to the photoreceptor cell nuclei as early as 6 hours of light exposure, showed that the number of TUNEL positive nuclei increased with light exposure, and revealed more DNA degradation in the superior quadrant. Our findings confirmed earlier morphologic observations that photic exposure triggers apoptosis of photoreceptor cells.