Wu J, Seregard S, Spångberg B, Oskarsson M, Chen E
St Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.
Eye (Lond). 1999 Aug;13 ( Pt 4):577-83. doi: 10.1038/eye.1999.142.
To explore cell death in blue light induced retinal damage.
Sprague-Dawley rats reared under cyclic light were exposed continuously to diffuse blue light (400-480 nm) at 0.64 W/m2 for 3 or 6 h after 22 h of dark adaptation. The rats were kept in darkness and killed immediately, 8, 16 and 24 h following light exposure. The retinal damage by the blue light was examined with a transmission electron microscope. The cell death was characterised by in situ terminal dUTP nick end labelling (TUNEL) and gel electrophoresis.
During the 24 h following light exposure, photoreceptor cell death was characterised by progressive condensation and margination of the chromatin, shrinkage or convolution and fragmentation of the nucleus, condensation of the cytoplasm, and formation of apoptotic bodies along with rapid removal of dying cells from damaged areas in the absence of inflammatory response. The TUNEL-positive nuclei were scattered individually in the outer nuclear layer just after light exposure. A wave of massive TUNEL labelling of photoreceptor nuclei peaked at 8-16 h and dropped at 24 h following light exposure. The distribution of TUNEL-positive nuclei was located predominantly at the upper temporal region of the retina, which was the most sensitive area to the damage caused by blue light. Furthermore, the multiples of internucleosomal cleavage of 180-200 base pairs were demonstrated at corresponding time points.
Photoreceptor cell apoptosis is seen early after the retina is damaged by blue light.
探讨蓝光诱导视网膜损伤中的细胞死亡。
将在周期性光照下饲养的Sprague-Dawley大鼠在暗适应22小时后，连续暴露于0.64W/m²的漫射蓝光（400-480nm）下3或6小时。光照后，将大鼠置于黑暗中，并在光照后立即、8、16和24小时处死。用透射电子显微镜检查蓝光对视网膜的损伤。通过原位末端脱氧核苷酸转移酶介导的缺口末端标记法（TUNEL）和凝胶电泳对细胞死亡进行表征。
在光照后的24小时内，光感受器细胞死亡的特征为染色质逐渐凝聚和边缘化、细胞核收缩或卷曲并碎片化、细胞质凝聚，以及凋亡小体的形成，同时在无炎症反应的情况下受损区域的死亡细胞迅速清除。光照后，TUNEL阳性细胞核在外核层单个散在分布。光感受器细胞核的大量TUNEL标记在光照后8-16小时达到峰值，并在24小时下降。TUNEL阳性细胞核的分布主要位于视网膜的颞上区域，这是对蓝光损伤最敏感的区域。此外，在相应时间点证实了180-200个碱基对的核小体间切割倍数。
蓝光损伤视网膜后早期可见光感受器细胞凋亡。
