Circadian rhythms in the incorporation and secretion of 3H-proline by odontoblasts in relation to incremental lines in rat dentin
Circadian rhythms in the incorporation and secretion of 3H-proline by odontoblasts in relation to incremental lines in rat dentin
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DOI：
10.1177/00220345980770110501
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发表时间：
1998-11-01
影响因子：
7.6
通讯作者：
Shinoda, H
中科院分区：
文献类型：
--
作者：
Ohtsuka, M;Saeki, S;Shinoda, H
动物牙本质中普遍存在昼夜节律增量线。它们被认为是由成牙细胞在24小时内的功能变化引起的。然而，节律性牙本质形成的机制尚不清楚。在本研究中，我们利用h -3-脯氨酸作为示踪剂的放射自显影技术研究了成牙细胞胶原合成和分泌活动是否存在24小时节律。6组大鼠适应12/12小时明暗光照循环2周后，分别在0000、0400、0800、1200、1600和2000点注射h -3-脯氨酸。注射后1小时，拔除上颌切牙，进行放射自显影研究。h -3-脯氨酸的银粒在环境光照期在成牙细胞和预备牙本质上最强烈，在黑暗期最低。峰值约为最小值的2倍。此外，在通过渗透微泵连续输注h -3-脯氨酸10天的大鼠牙本质中，h -3-脯氨酸的银粒大量分布在苏木精染色的暗纹上。因此，我们证明了成牙细胞在胶原合成和分泌方面具有昼夜节律。这些成牙细胞功能的节律可能是牙本质昼夜节律增量线的原因。
Circadian incremental lines are universally found in the dentin of animals. They are believed to be caused by functional changes in odontoblasts over 24 hrs. However, the mechanism of rhythmic dentin formation has not yet been elucidated In the present study, we investigated whether there is a 24-hour rhythm in the collagen-synthetic and secretory activities of odontoblasts by radioautography with H-3-proline as a tracer. Six different groups of rats were injected with H-3-proline at 0000, 0400, 0800, 1200, 1600, or 2000 after the animals had become acclimated to a 12/12-hour light-dark illumination cycle for 2 wks. One hour after the injection, the maxillary incisors were removed and processed for radioautographic study. The silver grains of H-3-proline were most intense over odontoblasts and predentin during the environmental light period, while the nadir occurred during the dark period. The peak value was approximately two-fold higher than the minimum value. Moreover, in the dentin from rats that had been infused with H-3-proline continuously for 10 days by means of osmotic minipumps, silver grains of H-3-proline were heavily distributed over the dark hematoxylin-stained incremental lines. Thus, we demonstrated that odontoblasts show circadian rhythm with regard to collagen synthesis and secretion. These rhythms in odontoblastic function may be responsible for circadian incremental lines in dentin.