Effect of melatonin on monochromatic light-induced changes in clock gene circadian expression in the chick liver
Effect of melatonin on monochromatic light-induced changes in clock gene circadian expression in the chick liver
复制标题
褪黑激素对单色光诱导的鸡肝脏时钟基因昼夜节律表达变化的影响
DOI：
10.1016/j.jphotobiol.2019.111537
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发表时间：
2019-08-01
影响因子：
5.4
通讯作者：
Chen, Yaoxing
中科院分区：
文献类型：
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作者：
Liu, Lei;Wang, Zixu;Chen, Yaoxing
光是昼夜节律系统中最重要的授时器，昼夜节律系统包括中心和外围振荡器。我们前期的研究发现，光波长可以影响雏鸡中枢振荡器褪黑素合成和时钟基因表达的节律。然而，单色光对外周振荡器的影响和褪黑激素的作用还有待澄清。本研究将216只初孵雏鸡分为正常、假手术和松果体切除3组，分别在白色（WL）、红色（RL）、绿色（GL）和蓝色（BL）光下饲养14天。在6个时间点每隔4 h采集血浆和肝脏样品。测定血浆褪黑激素浓度和肝时钟基因表达（cClock、cBmal1、cBmal2、cCry1、cCry2、cPer2、cPer3）用于昼夜节律分析。在完整的和假手术下WL鸡，所有的肝时钟基因表现出昼夜节律的表达沿着血浆褪黑激素的振荡。而正时钟基因在主观夜晚沿着褪黑素达到峰值，负时钟基因在主观白天或昼夜转换时间达到峰值。鸡暴露于单色光导致血浆褪黑激素和肝时钟基因的昼夜节律性不变，但是，他们的节奏参数显着影响。与WL相比，GL增强了褪黑素和各种时钟基因的表达量和幅度，而RL则相反。松果体切除术显著降低了肝时钟基因的表达，这与血浆褪黑激素浓度的降低一致，特别是对于GL组，并且导致肝时钟基因的表达显示出低中位和低振幅振荡，并且在单色光组之间没有统计学显著差异。因此，我们推测褪黑激素在光波长对鸡肝脏时钟基因节律的影响中起着关键作用。
Light is the most prominent zeitgeber of the circadian system, which contains central and peripheral oscillators. Our previous studies found that light wavelength could influence the rhythms of melatonin synthesis and clock gene expression in the central oscillator of chicks. However, the effect of monochromatic light on the peripheral oscillator and the role of melatonin have yet to be clarified. In this study, 216 newly hatched chicks were divided into three groups (intact, sham operation and pinealectomy) and were raised under white (WL), red (RL), green (GL) or blue (BL) light for 14 days. Their plasma and livers were sampled at 6 time points with 4-h intervals. Plasma melatonin concentration and liver clock gene expression (cClock, cBmal1, cBmal2, cCry1, cCry2, cPer2, cPer3) were measured for circadian rhythm analysis. In intact and sham operation chicks under WL, all liver clock genes showed circadian expression along with oscillations in plasma melatonin. However, positive clock genes peaked at subjective night along with melatonin, while negative clock genes peaked at subjective day or the shifting time of day-night. Chick exposure to monochromatic light led to an unaltered circadian rhythmicity in plasma melatonin and liver clock genes; however, their rhythmic parameters were notably influenced. Compared to WL, GL enhanced the mesor and amplitude of melatonin and all kinds of clock genes, whereas RL had the opposite effect. Pinealectomy significantly decreased expression of liver clock genes, which was consistent with the reduction in plasma melatonin concentration, especially for the GL group, and resulted in the expression of liver clock genes showing low-mesor and low-amplitude oscillations as well as no statistically significant differences among the monochromatic light groups. Thus, we speculated that melatonin plays a key role in the effects of light wavelength on clock gene rhythm in the chick liver.