Pulmonary and hemostatic toxicity of multi-walled carbon nanotubes and zinc oxide nanoparticles after pulmonary exposure in Bmal1 knockout mice.
BACKGROUND
Pulmonary exposure to nanoparticles (NPs) may affect, in addition to pulmonary toxicity, the cardiovascular system such as procoagulant effects, vascular dysfunction and progression of atherosclerosis. However, only few studies have investigated hemostatic effects after pulmonary exposure.


METHODS
We used Bmal1 (brain and muscle ARNT-like protein-1) knockout (Bmal1(-/-)) mice which have a disturbed circadian rhythm and procoagulant phenotype, to study the pulmonary and hemostatic toxicity of multi-walled carbon nanotubes (MWCNTs) and zinc oxide (ZnO) NPs after subacute pulmonary exposure. Bmal1(-/-) and wild-type (Bmal1(+/+)) mice were exposed via oropharyngeal aspiration, once a week, during 5 consecutive weeks, to a cumulative dose of 32 or 128 μg MWCNTs or 32 or 64 μg ZnO NPs.


RESULTS
MWCNTs caused a pronounced inflammatory response in the lung with increased cell counts in the broncho-alveolar lavage and increased secretion of interleukin-1β and cytokine-induced neutrophil chemo-attractant (KC), oxidative stress (increased ratio of oxidized versus reduced glutathione and decreased total glutathione) as well as anemic and procoagulant effects as evidenced by a decreased prothrombin time with increased fibrinogen concentrations and coagulation factor (F)VII. In contrast, the ZnO NPs seemed to suppress the inflammatory (decreased neutrophils in Bmal1(-/-) mice) and oxidative response (increased total glutathione in Bmal1(-/-) mice), but were also procoagulant with a significant increase of FVIII. The procoagulant effects, as well as the significant correlations between the pulmonary endpoints (inflammation and oxidative stress) and hemostasis parameters were more pronounced in Bmal1(-/-) mice than in Bmal1(+/+) mice.


CONCLUSIONS
The Bmal1(-/-) mouse is a sensitive animal model to study the procoagulant effects of engineered NPs. The MWCNTs and ZnO NPs showed different pulmonary toxicity but both NPs induced procoagulant effects, suggesting different mechanisms of affecting hemostasis. However, the correlation analysis suggests a causal association between the observed pulmonary and procoagulant effects.
Department of Public Health and Primary Care, Occupational and Environmental Toxicology, KU Leuven, Leuven, Belgium. Katrien.luyts@med.kuleuven.be.
Katrien
K
Luyts
Department of Public Health and Primary Care, Occupational and Environmental Toxicology, KU Leuven, Leuven, Belgium. Stijn.smulders@med.kuleuven.be.
Stijn
S
Smulders
Department of Public Health and Primary Care, Occupational and Environmental Toxicology, KU Leuven, Leuven, Belgium. Dorota.napierska@gmail.com.
Dorota
D
Napierska
Department of Cardiovascular sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium. Soetkin.VanKerckhoven@med.kuleuven.be.
Soetkin
S
Van Kerckhoven
Department of Public Health and Primary Care, Laboratory for Occupational and Environmental Hygiene, KU Leuven, Leuven, Belgium. Katrien.Poels@med.kuleuven.be.
Katrien
K
Poels
Department of Public Health and Primary Care, Occupational and Environmental Toxicology, KU Leuven, Leuven, Belgium. Hans.Scheers@med.kuleuven.be.
Hans
H
Scheers
Department of Cardiovascular sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium. Bianca.Hemmeryckx@med.kuleuven.be.
Bianca
B
Hemmeryckx
Department of Public Health and Primary Care, Occupational and Environmental Toxicology, KU Leuven, Leuven, Belgium. Ben.Nemery@med.kuleuven.be.
Ben
B
Nemery
Department of Cardiovascular sciences, Center for Molecular and Vascular Biology, KU Leuven, Leuven, Belgium. Marc.Hoylaerts@med.kuleuven.be.
Marc F
MF
Hoylaerts
Department of Public Health and Primary Care, Occupational and Environmental Toxicology, KU Leuven, Leuven, Belgium. peter.hoet@med.kuleuven.be.
Peter H M
PH
Hoet
D056930:ARNTL Transcription Factors / Q000235:genetics / Q000378:metabolism; D000393:Air Pollutants / Q000737:chemistry / Q000633:toxicity*; D000743:Anemia, Hemolytic / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity; D003029:Coagulants / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D006461:Hemolysis / Q000187:drug effects; D018836:Inflammation Mediators / Q000819:agonists / Q000378:metabolism; D019570:Inhalation Exposure / Q000009:adverse effects*; D008168:Lung / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D053768:Metal Nanoparticles / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity*; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D011014:Pneumonia / Q000139:chemically induced* / Q000276:immunology / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D019851:Thrombophilia / Q000139:chemically induced* / Q000276:immunology / Q000378:metabolism; D059551:Toxicity Tests, Subacute; D015034:Zinc Oxide / Q000008:administration & dosage / Q000737:chemistry / Q000633:toxicity
D056930:ARNTL Transcription Factors; D000393:Air Pollutants; D000894:Anti-Inflammatory Agents, Non-Steroidal; C538961:Bmal1 protein, mouse; D003029:Coagulants; D018836:Inflammation Mediators; D037742:Nanotubes, Carbon; D015034:Zinc Oxide