| 研究課題/領域番号 |
20K11551
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| 研究機関 | お茶の水女子大学 |
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研究代表者 |
グホ サビン お茶の水女子大学, 理学部, 学部教育研究協力員 (30453179)
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| 研究分担者 |
宮本 泰則 お茶の水女子大学, ヒューマンライフイノベーション研究所, 准教授 (50272737)
和気 秀文 順天堂大学, スポーツ健康科学部, 教授 (50274957)
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| 研究期間 (年度) |
2020-04-01 – 2024-03-31
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| キーワード | nanoplastics exposure / blood pressure / hear rate / urine osmolality / area postrema / cardiovascular centers |
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| 研究実績の概要 |
Recent data suggests that humans are regularly exposed to plastic nanoparticles (NPs) via the food chain. Moreover, NPs were shown to cross biological membranes, alter gene expression, and trigger behaviour changes in marine animals. However, the impact of NPs on terrestrial mammalian health is poorly studied. We examined physiological and biological parameters of rats orally exposed to nanoplastics (NPs). Three weeks-old male Wistar rats were housed individually in metabolic cages and were trained to drink a 3% sucrose solution from a syringe. At the age of five weeks, rats were fed daily with the solution supplemented with 50 nm polystyrene NPs (12.5 mg/kg body weight) either amino-modified (NP+) or carboxy-modified (NP-), or with water (CONTROL), for two months. Body weight, blood pressure, hear rate, water and food intake, and urine volume were regularly recorded. Physico-chemical characteristics of urine were also assessed.
Whilst the basal level of blood pressure and heart rate exhibited a tendency to decrease in NP groups, the urine osmolality of those rats significantly increased after two months exposure. Our data suggests that a chronic oral exposure to NPs affects cardiovascular and osmoregulation mechanisms in rats.
At the end of exposure experiments, the rats were perfused, their brains were fixed and frozen for investigation of inflammatory characteristics in blood-brain barrier (BBB) free areas (e.g. Area Postrema) and other cardiovascular centers (Nucleus Tractus Solitarii) by using immunofluorescence and confocal microscopy in the next fiscal year.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The main goals of our research for FY2020-2021 were to assess the effects of a chronic oral exposure to NPs on rat physiological parameters, and blood inflammatory markers. These goals were for the most part achieved. However, the analysis of inflammatory markers (e.g. AchE) in the blood remained inconclusive and needs to be repeated. The analysis of urine osmolality was performed in addition to the planed experiments, and showed significant differences between groups.
Another goal of our research was to investigate the distribution of PSNPs in BBB free areas (e.g. Area Postrema) and other cardiovascular centers (e.g. Nucleus Tractus Solitarii) by using fluorescent NPs (F-PSNPs) and confocal microscopy on rat brain slices. F-PSNPs could not be successfully detected in the brain of rats fed F-PSNPs for 3 days, probably because of the low level of F-PSNPs accumulated in brain tissue. The experiments will be repeated after intravenous injection of F-PSNP in rats to increase the circulating level of F-PSNPs in blood.
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| 今後の研究の推進方策 |
During FY2021-2022:
1) Blood inflammatory markers and urine physico-chemical characteristics will be further investigated.
2) The distribution of NPs in BBB-free areas (e.g. Area Postrema) and other cardiovascular centers (e.g. Nucleus Tractus Solitarii) will be assessed by confocal microscopy after intravenous injection of F-PSNPs in rats.
3) The inflammatory state of BBB-free areas and other cardiovascular centers will be investigated by comparing the morphology of microglia between groups. Microglia will be analyzed by using immunofluorescence experiments with Iba-1 antibody, a marker of microglial cells, and confocal microscopy.
4) The expression of inflammation-related genes will be investigated at transcript level by using RT-qPCR on BBB-free areas (e.g. Area Postrema) and other cardiovascular centers (e.g. Nucleus Tractus Solitarii) of the brain of rats chronically orally exposed to NPs.
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| 次年度使用額が生じた理由 |
Experiments of chronic oral exposure to NPs are being repeated on a second batch of rats to confirm our first data, and the physico-chemical characteristics of rats blood and urine remain to be investigated. Therefore, the amount of money transferred from the FY2020 to the FY2021 will be used to analyze the physico-chemical characteristics of rats blood and urine of the second batch of rats (e.g. osmolality, composition).
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