Effect of pinealectomy on the circadian clock of the chick retina under different monochromatic lights
Effect of pinealectomy on the circadian clock of the chick retina under different monochromatic lights
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不同单色光下松果体切除术对雏鸡视网膜生物钟的影响
DOI：
10.1080/07420528.2019.1566740
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发表时间：
2019-04-03
影响因子：
2.8
通讯作者：
Chen, Yaoxing
中科院分区：
文献类型：
--
作者：
Bian, Jiang;Wang, Zixu;Chen, Yaoxing
鸟类昼夜节律起搏器由视网膜、松果体和视交叉上核组成。作为一个完整的输入-起搏器-输出系统，这些结构中的每一个都在神经内分泌回路中连接，以影响下游过程和外周振荡。虽然我们之前的研究发现单色光会影响小鸡视网膜中时钟基因的昼夜节律，但松果体对单色光下视网膜昼夜节律反应的影响仍不清楚。在本研究中，总共144只雏鸡，包括假手术组和松果体切除组，暴露于白色、红色、绿色或蓝色光。光照2周后，检测视网膜中6个核心时钟基因（cClock、cBmal 1、cCry 1、cCry 2、cPer 2和cPer 3）、黑视素（cOpn 4 -1、cOpn 4 -2）、芳基烷基胺N-乙酰转移酶（cAanat）和褪黑素的昼夜表达。cBmal 1、cCry 1、cPer 2、cPer 3、cOpn 4 -1、cOpn 4 -2和cAanat基因以及褪黑素在假手术组和松果体切除组中在不同单色光下均具有昼夜节律性表达，而cClock和cCry 2在所有光处理组中均具有昼夜节律性表达。松果体切除后，鸡视网膜时钟基因、黑视素、cAanat和褪黑素的节律性没有改变，尤其是cBmal 1、cOpn 4 -1、cOpn 4 -2、cAanat和褪黑素的介导、振幅和相位。但与白色光组相比，绿色光可增加松果体切除雏鸡正性生物钟基因cBmal 1、cAanat、cOpn 4 -1和cOpn 4 -2的mRNA表达以及褪黑素含量，而红光可降低其表达。这些结果表明，鸡视网膜是一个相对独立的昼夜振荡器从松果体，其昼夜节律（包括光感受，分子钟和褪黑激素的输出）不被松果体切除后改变。此外，绿色光通过加速黑视素和正调节时钟基因cBmal 1和cClock的表达来增加眼cAanat表达和褪黑激素合成。
ABSTRACT The avian circadian rhythm pacemaker is composed of the retina, pineal gland and suprachiasmatic nucleus. As an intact input-pacemaker-output system, each of these structures is linked within a neuroendocrine loop to influence downstream processes and peripheral oscillations. While our previous study found that monochromatic light affected the circadian rhythms of clock genes in the chick retina, the effect of the pineal gland on the response of the retinal circadian clock under monochromatic light still remains unclear. In this study, a total of 144 chicks, including sham-operated and pinealectomized groups, were exposed to white, red, green or blue light. After 2 weeks of light illumination, the circadian expression of six core clock genes (cClock, cBmal1, cCry1, cCry2, cPer2 and cPer3), melanopsin (cOpn4-1, cOpn4-2), Arylalkylamine N-acetyltransferase (cAanat) and melatonin was examined in the retina. The cBmal1, cCry1, cPer2, cPer3, cOpn4-1, cOpn4-2 and cAanat genes as well as melatonin had circadian rhythmic expression in both the sham-operated and pinealectomized groups under different monochromatic lights, while cClock and cCry2 had arrhythmic 24 h profiles in all of the light-treated groups. After pinealectomy, the rhythmicity of the clock genes, melanopsins, cAanat and melatonin in the chick retina did not change, especially the mesors, amplitudes and phases of cBmal1, cOpn4-1, cOpn4-2, cAanat and melatonin. Compared to the white light group, however, green light increased the mRNA expression of the positive-regulating clock genes cBmal1, cAanat, cOpn4-1 and cOpn4-2 as well as the melatonin content in pinealectomized chicks, whereas red light decreased their expression. These results suggest that the chick retina is a relatively independent circadian oscillator from the pineal gland, whose circadian rhythmicity (including photoreception, molecular clock and melatonin output) is not altered after pinealectomization. Moreover, green light increases ocular cAanat expression and melatonin synthesis by accelerating the expression of melanopsin and positive-regulating clock genes cBmal1 and cClock.