2007 Fiscal Year Final Research Report Summary
Development of artificial environments to regulate fetal growth through controlled light exposure
| Project/Area Number |
18591215
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Embryonic/Neonatal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
OHTA Hidenobu Tohoku University, Tohoku University Hospital, Assistant Professor (80422103)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUDA Tadashi Tohoku University Hospital, 病院, Assosiate Professor (50361100)
SAITO Masatoshi Tohoku University Hospital, 病院, Seniot Residents (00451584)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Perinatal medicine / Fetus / Preterm infant / Artificial incubation |
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| Research Abstract |
The purpose of our study was to clarify the effects that lighting conditions have on gene expressions of environmental sensors and on development of immature organs. By using the models of sheep fetus and rat neonates, we examined the effects of light on peripheral tissues or organs such as mononuclear blood cells and adrenals.
1. Sheep fetus model: At 102 d gestation, Suffolk ewes with timed pregnancies underwent surgery while anesthetized with intrathecal tetracaine hydrochloride and intravenous ketamine hydrochloride. After laparotomy and hysterotomy, three electrodes were fixed to the fetal chest wall and polyvinyl catheters were placed in the fetal superior vena cava, inferior vena cava, distal abdominal aorta, and amniotic cavity. All catheters and electrodes were exteriorized through a small incision in the flank of each ewe. The ewes were unrestrained and housed in individual cages, with free access to water and food under a 12 h light (fluorescent light, 200 lux): 12 h dark (LD
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) cycle throughout the study period. A recovery period of 7 d was allowed before the experiments, and during that time appropriate antibiotics were administered to the mother, fetus, and amniotic cavity. At 109 d gestation the fetal blood was sampled from the superior vena cava through the catheters. The mononuclear cells (MNCs) were isolated from 5 mL of the whole blood by single-step separation over a Ficoll-Hypaque solution. From the MNCs ovine mRNAs were extracted and ovine Perl, Per2, Bmall and Cryl expression were confirmed by real-time PCR. In this study we successfully established a pregnant sheep model to analyze the effects of lighting conditions on gene expressions of environmental sensors and on development of the immature organs of sheep fetuses.
2. Rat neonate model: Neonatal rats were maintained under a 12 h light (fluorescent light, 200 lux): 12 h dark (LD) cycle with their dams which had free access to food and water from birth (postnatal day 0) to postnatal day 4. From the dark period of postnatal day 4, both neonatal rats and a dam were transferred to constant dark for 2 days. At circadian time 16 of postnatal day 6, which is the equivalent time of 4 hours after dark onset, neonatal rats were exposed to light stimulus of 3000 lux for 30 min. In situ hybridization revealed that Perl mRNA expression in the adrenal cortex of neonatal rats significantly increased in the 120 min after light exposure compared to that in the beginning of the light stimuli (p>0.05, one-way ANOVA). However, increase in Per2 mRNA expression was not detected in the adrenal cortex of the neonatal rats. The study demonstrated 1) that the adrenal cortex of rat neonates was affected by light stimulus at circadian time 16 (during subjective night) and 2) peripheral organs such as the adrenal clock can be entrained by the light environment in early postnatal development. Less
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[Presentation] Visual world for preterm infants2007
Author(s)
Hidenobu Ohta
Organizer
Seminar in morpho-functional analysis
Place of Presentation
Kobe University Graduate School, Dept. of Agriculture, Kobe
Year and Date
2007-06-08
Description
「研究成果報告書概要(欧文)」より
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[Book] きちんと分かる時計遺伝子2007
Author(s)
太田英伸 (産業技術総合研究所 編)
Total Pages
183-192
Publisher
白日社(東京)
Description
「研究成果報告書概要(和文)」より
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[Book] Visual environments for neonates and preterm infants2007
Author(s)
Hidenobu Ohta
Total Pages
10
Publisher
In Yamaguchi, M & Kanazawa, S (Eds.), Handbook for perceptions in developmental psychology: Infantile perceptional world explored by psychological experiments. Kyoto: Kitaohjishobo
Description
「研究成果報告書概要(欧文)」より
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