Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages

Mei Yang,1 Minfang Zhang,1 Hideaki Nakajima,1 Masako Yudasaka,1,2 Sumio Iijima,2 Toshiya Okazaki11Nanotube Application Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan; 2Faculty of Science & Technology, Meijo Universit...

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Autores principales:	Yang M, Zhang M, Nakajima H, Yudasaka M, Iijima S, Okazaki T
Formato:	article
Lenguaje:	EN
Publicado:	Dove Medical Press 2019
Materias:	carbon nanomaterials biodegradation cytotoxicity cellular uptake Medicine (General) R5-920
Acceso en línea:	https://doaj.org/article/76d9cd83219b436cb10e927f633520a4
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spelling	oai:doaj.org-article:76d9cd83219b436cb10e927f633520a42021-12-02T06:47:53ZTime-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages1178-2013https://doaj.org/article/76d9cd83219b436cb10e927f633520a42019-04-01T00:00:00Zhttps://www.dovepress.com/time-dependent-degradation-of-carbon-nanotubes-correlates-with-decreas-peer-reviewed-article-IJNhttps://doaj.org/toc/1178-2013Mei Yang,1 Minfang Zhang,1 Hideaki Nakajima,1 Masako Yudasaka,1,2 Sumio Iijima,2 Toshiya Okazaki11Nanotube Application Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan; 2Faculty of Science & Technology, Meijo University, Tempaku-ku, Nagoya 468-8502, JapanIntroduction and objective: With the increase in carbon nanotube-based products on the commercial market, public concern regarding the possible toxicity of these nanomaterials has attracted much attention. Although previous studies found no obvious toxicity related to carbon nanotubes (CNTs), their safety has not been established because long-term evaluation is still needed. In vitro assays are used to understand the toxicity of nanomaterials. However, the data published so far were generated in short-term assays in which cells are continuously exposed to CNTs. Therefore, the objective of this study is to quantitatively assess the relative long-term cytotoxicity and degradation of CNTs after uptake by macrophages.Methods: We used macrophage cell line of RAW 264.7 and primary rat Kupffer cells to investigate macrophage uptake of CNTs as well as their quantity changes up to a relatively late time point after uptake (7 days) by measuring optical absorbance in the near infrared region and Raman spectra of CNTs in the cell lysates. The time-dependent cytotoxicity was evaluated by measuring reactive oxygen species (ROS), glutathione, cell viability, and caspase 3/7 activity in 1–7 days.Results: CNTs were degraded by approximately 25–30% within first 4 days after uptake; however, and no additional degradation occurred for the remainder of the 7-day test period. Generation of ROS by macrophages decreased as CNT degradation occurred, returning to control levels by Day 7. In the meantime, the glutathione level gradually recovered over time. There were no changes in cell viability or caspase 3/7 activation during CNT degradation.Conclusion: These results confirm that degradation of CNTs by macrophages is associated with ROS generation. The data also suggest that CNT cytotoxicity decreases as they are degraded.Keywords: carbon nanomaterials, biodegradation, cytotoxicity, cellular uptakeYang MZhang MNakajima HYudasaka MIijima SOkazaki TDove Medical Pressarticlecarbon nanomaterialsbiodegradationcytotoxicitycellular uptakeMedicine (General)R5-920ENInternational Journal of Nanomedicine, Vol Volume 14, Pp 2797-2807 (2019)
institution	DOAJ
collection	DOAJ
language	EN
topic	carbon nanomaterials biodegradation cytotoxicity cellular uptake Medicine (General) R5-920
spellingShingle	carbon nanomaterials biodegradation cytotoxicity cellular uptake Medicine (General) R5-920 Yang M Zhang M Nakajima H Yudasaka M Iijima S Okazaki T Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
description	Mei Yang,1 Minfang Zhang,1 Hideaki Nakajima,1 Masako Yudasaka,1,2 Sumio Iijima,2 Toshiya Okazaki11Nanotube Application Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan; 2Faculty of Science & Technology, Meijo University, Tempaku-ku, Nagoya 468-8502, JapanIntroduction and objective: With the increase in carbon nanotube-based products on the commercial market, public concern regarding the possible toxicity of these nanomaterials has attracted much attention. Although previous studies found no obvious toxicity related to carbon nanotubes (CNTs), their safety has not been established because long-term evaluation is still needed. In vitro assays are used to understand the toxicity of nanomaterials. However, the data published so far were generated in short-term assays in which cells are continuously exposed to CNTs. Therefore, the objective of this study is to quantitatively assess the relative long-term cytotoxicity and degradation of CNTs after uptake by macrophages.Methods: We used macrophage cell line of RAW 264.7 and primary rat Kupffer cells to investigate macrophage uptake of CNTs as well as their quantity changes up to a relatively late time point after uptake (7 days) by measuring optical absorbance in the near infrared region and Raman spectra of CNTs in the cell lysates. The time-dependent cytotoxicity was evaluated by measuring reactive oxygen species (ROS), glutathione, cell viability, and caspase 3/7 activity in 1–7 days.Results: CNTs were degraded by approximately 25–30% within first 4 days after uptake; however, and no additional degradation occurred for the remainder of the 7-day test period. Generation of ROS by macrophages decreased as CNT degradation occurred, returning to control levels by Day 7. In the meantime, the glutathione level gradually recovered over time. There were no changes in cell viability or caspase 3/7 activation during CNT degradation.Conclusion: These results confirm that degradation of CNTs by macrophages is associated with ROS generation. The data also suggest that CNT cytotoxicity decreases as they are degraded.Keywords: carbon nanomaterials, biodegradation, cytotoxicity, cellular uptake
format	article
author	Yang M Zhang M Nakajima H Yudasaka M Iijima S Okazaki T
author_facet	Yang M Zhang M Nakajima H Yudasaka M Iijima S Okazaki T
author_sort	Yang M
title	Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
title_short	Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
title_full	Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
title_fullStr	Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
title_full_unstemmed	Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
title_sort	time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages
publisher	Dove Medical Press
publishDate	2019
url	https://doaj.org/article/76d9cd83219b436cb10e927f633520a4
work_keys_str_mv	AT yangm timedependentdegradationofcarbonnanotubescorrelateswithdecreasedreactiveoxygenspeciesgenerationinmacrophages AT zhangm timedependentdegradationofcarbonnanotubescorrelateswithdecreasedreactiveoxygenspeciesgenerationinmacrophages AT nakajimah timedependentdegradationofcarbonnanotubescorrelateswithdecreasedreactiveoxygenspeciesgenerationinmacrophages AT yudasakam timedependentdegradationofcarbonnanotubescorrelateswithdecreasedreactiveoxygenspeciesgenerationinmacrophages AT iijimas timedependentdegradationofcarbonnanotubescorrelateswithdecreasedreactiveoxygenspeciesgenerationinmacrophages AT okazakit timedependentdegradationofcarbonnanotubescorrelateswithdecreasedreactiveoxygenspeciesgenerationinmacrophages
_version_	1718399759673196544

Time-dependent degradation of carbon nanotubes correlates with decreased reactive oxygen species generation in macrophages

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