In Situ Measurement of Vapor Uptake in the Rodent Upper Respiratory Tract

John B. Morris1, Joseph A. Cichocki1, Gregory J. Smith1

1 Toxicology Program, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut
Publication Name:  Current Protocols in Toxicology
Unit Number:  Unit 24.1
DOI:  10.1002/0471140856.tx2401s55
Online Posting Date:  February, 2013
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Abstract

The response of respiratory tract tissue target sites to inhaled vapors depends on the amount of inhaled vapor that is delivered to those sites. Direct measurement of vapor absorption within a specific airway of the living animal requires that the airway be isolated, which currently can only be performed on the upper airways. Towards this end, the upper respiratory tract (all airways anterior to the larynx) is surgically isolated in the anesthetized rat by tracheostomy and insertion of two endotracheal tubes, one leading anteriorly and the other posteriorly. The surgically manipulated animal is then placed in a nose‐only inhalation chamber and test‐vapor‐laden air is drawn through the isolated upper airways under defined air flow conditions via the anterior endotracheal tube. The animal spontaneously respires clean air into the lungs during this procedure via the posterior endotracheal tube. The concentration of test vapor in air entering and the air exiting the upper airways is measured by gas chromatography, and the difference in concentrations provides a measure of vapor absorption in that site. A rich database is available on upper respiratory tract vapor absorption as measured by this methodology, to which newly obtained data can be compared. These data have been instrumental not only in understanding the regional airway toxicity of inspired vapors, but also for developing mathematical models to describe inhaled vapor dosimetry. Curr. Protoc. Toxicol. 55:24.1.1‐24.1.10. © 2013 by John Wiley & Sons, Inc.

Keywords: inhalation toxicology; vapor absorption; airway toxicity

     
 
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Table of Contents

  • Introduction
  • Strategic Planning
  • Basic Protocol 1: In Vitro Measurement of Vapor Uptake in the Rodent Upper Respiratory Tract
  • Commentary
  • Literature Cited
  • Figures
     
 
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Materials

Basic Protocol 1: In Vitro Measurement of Vapor Uptake in the Rodent Upper Respiratory Tract

  Materials
  • Adult rats (e.g., F344, 8‐12 week old, 180‐220 g)
  • Test material (see Strategic Planning)
  • Urethane (Sigma‐Aldrich)
  • Testing apparatus, including nose‐only inhalation chamber and air sampling train (see Strategic Planning and Fig. )
  • Glass containers or inert bags (e.g., Tedlar, depending on chemical compatibility)
  • Syringe and 23‐ to 25‐G needle
  • Surgical tools, e.g., scalpel, forceps
  • Micropipet tip
  • Thread (e.g., nylon)
  • Endotracheal tubes (e.g., PE205 intramedic polyethylene tubing)
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Figures

Videos

Literature Cited

Literature Cited
   Aharonson, E.F., Menkes, H., Gurtner, G., Swift, D.L., and Proctor, D.F. 1974. Effect of respiratory airflow rate on removal of soluble vapors by the nose. J. Appl. Physiol. 37:654‐657.
   Cameron, G.R., Gaddum, J.H., and Short, R.H.D. 1946. The absorption of war gases by the nose. J. Pathol. 58:449‐455.
   Frank, N.R., Yoder, R.E., Brain, J.D., and Yokoyama, E. 1969. SO2 (35S labeled) absorption by the nose and mouth under conditions of varying concentration and flow. Arch. Environ. Health 18:315‐322.
   Gloede, E.C., Baldino, J.A., and Morris, J.B. 2011. A validated hybrid computational fluid dynamics‐physiologically based pharmacokinetic model for respiratory tract vapor absorption in the human and rat and its application to inhalation dosimetry of diacetyl. Toxicol. Sci. 123:231‐246.
   Haggard, H.W. 1924. The absorption, distribution and elimination of ethyl ether. V. The importance of the volume of breathing during the induction and termination of ether anesthesia. J. Biol. Chem. 59:795‐802.
   Hubbs, A.F., Goldsmith, W.T., Kashon, M.L., Frazer, D., Mercer, R.R., Battelli, L.A., Kullman, G.J., Schwegler‐Berry, D., Friend, S., and Castranova, V. 2008. Respiratory toxicologic pathology of inhaled diacetyl in Sprague‐Dawley rats. Toxicol. Pathol. 36:330‐344.
   Kreiss, K., Gomaa, A., Kullman, G., Fedan, K., Simoes, E.J., and Enright, P.L. 2002. Clinical bronchiolitis obliterans in workers at a microwave‐popcorn plant. N. Engl. J. Med. 347:330‐338.
   Miller, F.J., Menzel, D.B., and Coffin, D.L. 1978. Similarity between man and laboratory animals in regional pulmonary deposition of ozone. Environ. Res. 17:84‐101.
   Morris, J.B. 1997. Uptake of acetaldehyde and aldehyde dehydrogenase levels in the upper respiratory tracts of the mouse, rat, hamster and guinea pig. Fundamen. Appl. Toxicol. 35:91‐100.
   Morris, J.B. 1999. A method for measuring upper respiratory tract vapor uptake and its applicability to quantitative inhalation risk assessment. Inhal. Toxicol. 11:101‐123.
   Morris, J.B. 2012. Biologically‐based modeling insights in inhaled vapor absorption and dosimetry. Pharmacol. Ther. 136:401‐413.
   Morris, J.B. and Buckpitt, A.R. 2009. Upper respiratory tract uptake of naphthalene. Toxicol. Sci. 111:383‐391.
   Morris, J.B. and Hubbs, A.F. 2009. Inhalation dosimetry of diacetyl and butyric acid, two components of butter flavoring vapors. Toxicol. Sci. 108:173‐183.
   Morris, J.B., Stanek, J., and Gianutsos, G. 1999. Sensory nerve‐mediated immediate nasal responses to inspired acrolein. J. Appl. Physiol. 87:1877‐1886.
   U.S. Environmental Protection Agency (USEPA). 2009. Advances in Inhalation Dosimetry of Gases and Vapors with Portal of Entry Effects in the Upper Respiratory Tract (Vol. EPA/600/R‐09/072). Washington, D.C.
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