The Effects of Inhaled Multiwalled Carbon Nanotubes on Systemic Blood Pressure and the Autonomic Nervous System in Spontaneously Hypertensive Rats

Details

• Personal Author:
  Kan H ; Kashon ML ; McKinney W ; South T
• Description:
  It is well documented that the autonomic nervous system (ANS) plays a critical role in controlling cardiovascular functions including heart rate, cardiac contractility and blood pressure (BP). In previous studies, we reported that inhalation of multi-walled carbon nanotubes (MWCNTs) elevated systemic BP, which was associated with an altered activity in the ANS in normotensive rats. In addition, we also reported that the BP of spontaneously hypertensive (SH) rats was greatly increased in response to pulmonary MWCNT exposure compared to normotensive rats. The available evidence indicates that in essential hypertension, there is a deteriorated balance between sympathetic and parasympathetic activity. The present study investigated the effects of inhaled MWCNTs on the ANS and the role of peripheral neurons in regulation of cardiovascular function after exposure of SH rats to MWCNTs. SH Wistar rats were pre-implanted with a telemetry device and exposed by inhalation to MWCNTs at a concentration of 2 mg/m3 for 5 h/day for three consecutive days. The real-time EKGs and systemic BP were recorded by a telemetry system at pre-exposure, during exposure, 1 day post-exposure and 7 days post-exposure. The activity of the ANS in response to MWCNT exposure was determined by heart rate variability (HRV) analysis. The non-selective transient receptor potential (TRP) channel blocker, ruthenium red (2.5 mg/kg), was injected intraperitoneally 1 h before MWCNT exposure to study the role of peripheral neurons in regulating cardiovascular function and activity of the ANS after pulmonary MWCNT exposure. Inhalation of MWCNTs elevated systemic BP and increased the variance of the root mean square of successive differences (RMSSD) between adjacent R-R intervals (p < 0.01) and the high frequency (HF) power (p < 0.01). Both RMSSD and HF are metrics corresponding to autonomic nerve influences on cardiovascular function. Pretreatment with ruthenium red prevented those increases. Our study indicates that pulmonary exposure to MWCNTs significantly altered the activity of the ANS and increased the BP via a peripheral neuron-regulated pathway in SH rats. [Description provided by NIOSH]
• Subjects:
  Cardiovascular Diseases Cardiovascular System Environmental Exposure Laboratories Lung Occupational Health Respiratory System Safety Toxicology
• Keywords:
  Autonomic Nervous System Biological Effects Biological Function Blood Pressure Carbon Nanotubes Cardiovascular Function Cellular Reactions CNT Exposure Assessment Exposure Levels Gene Regulation Heart Rate Hypertension Inhalation Laboratory Animals Laboratory Testing Multi-walled Carbon Nanotubes MWCNT Nanotoxicology Nanotubes Nervous System Function Parasympathetic Nervous System Peripheral Nervous System Pulmonary System

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• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  California ; OSHA Region 3 ; OSHA Region 9 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  174
• Issue:
  1
• NIOSHTIC Number:
  nn:20058999
• Citation:
  Toxicologist 2020 Mar; 174(1):499
• CAS Registry Number:
  Carbon nanotubes (CAS RN 308068-56-6) ; Ruthenium red (CAS RN 11103-72-3)
• Federal Fiscal Year:
  2020
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 59th Annual Meeting and ToxExpo, March 15-19, 2020, Anaheim, California
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:9591227d841af0959cd9e2bf93c0894068f341518f20731a229ff259befdc212d676001b0b25bba263a16858e293bc896f69a1ee1fdbabe436d48db5cf0d54a6
• Download URL:
  https://stacks.cdc.gov/view/cdc/223338/cdc_223338_DS1.pdf
• File Type:
  [PDF - 525.10 KB ]