The central biological clock system of bird is formed by hypothalamus suprachiasmatic nucleus, pineal gland and retina thereby interacting with each other in a neuroendocrine loop. Previous results have confirmed that monochromatic light can influence the clock genes in the pineal gland, hypothalamus and retina of chicks in vivo. The present work was conducted to study whether the cultured retinal tissue of chick could maintain the circadian oscillation and whether the monochromatic light affect the expression level of cultured retinal circadian clock in vitro. Retinal tissues of 0-day-old chicks were cultured in vitro under 4 light treatments (white, red, green and blue lights) with light dark cycle 12:12 and constant dark. The tissues and culture medium were collected every each 4 h. Melanopsin, clock genes, cAanat, the positive-regulating clock proteins and melatonin were measured. The results showed that cOpn4-1, cOpn4-2, cBmal1, cCry1, cPer2, cPer3, cAanat and melatonin concentrations possessed a significant circadian rhythm in cultured chick retina tissues under different monochromatic lights; while, in constant dark, cBmal1, cCry1, cPer2, cPer3, cAanat and melatonin concentration possessed a significant circadian rhythm. Green light promoted the circadian expression level of cOpn4-1, cOpn4-2, cBmal1, cAanat and BMAL1 proteins and the circadian rhythm of melatonin secretion of retina by increasing the mesors and amplitudes. In addition, green light significantly increased the average expression levels of cClock, cBmal2 and CLOCK proteins which were expressed arrhythmically. Results suggested that the retina is a central oscillator with autonomous circadian rhythm. In isolated retina tissues, green light activated the expression of melanopsin and promoted the expression of positive-regulating clock genes, thereby up-regulating the expression of cAanat and resulting the increasing of the synthesis and secretion of melatonin.

中文翻译：

---

单色光对培养的鸡视网膜组织昼夜节律的影响。

鸟类的中央生物钟系统是由下丘脑上视交叉核，松果体和视网膜形成的，从而在神经内分泌环中相互作用。先前的结果已经证实，单色光可以在体内影响小鸡的松果体，下丘脑和视网膜中的时钟基因。目前的工作是研究鸡的视网膜组织是否能维持昼夜节律振荡，单色光是否会影响体外培养的昼夜节律钟的表达水平。在4个光照处理（白，红，绿和蓝光）下，以12:12的暗周期和恒定的暗度在体外培养0日龄小鸡的视网膜组织。每4小时收集一次组织和培养基。黑色素，时钟基因，cAanat，测定了正调节时钟蛋白和褪黑激素。结果表明，在不同单色光下培养的雏鸡视网膜组织中，cOpn4-1，cOpn4-2，cBmal1，cCry1，cPer2，cPer3，cAanat和褪黑激素的浓度具有明显的昼夜节律。而在持续的黑暗中，cBmal1，cCry1，cPer2，cPer3，cAanat和褪黑激素的浓度具有明显的昼夜节律。绿光通过增加膜面和振幅来促进cOpn4-1，cOpn4-2，cBmal1，cAanat和BMAL1蛋白的昼夜节律表达水平和褪黑激素分泌的昼夜节律。此外，绿光显着提高了心律失常表达的cClock，cBmal2和CLOCK蛋白的平均表达水平。结果表明，视网膜是具有自主昼夜节律的中央振荡器。在分离的视网膜组织中，绿光激活了黑色素的表达并促进了正调节时钟基因的表达，从而上调了cAanat的表达，并导致褪黑素的合成和分泌增加。