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Altered ion transport and responsiveness to methacholine and hyperosmolarity in air interface-cultured guinea-pig tracheal epithelium.

Authors
Fedan-JS; Wu-DX-Y; Van Scott-MR
Source
J Pharmacol Toxicol Methods 2007 Mar-Apr; 55(2):135-143
NIOSHTIC No.
20031587
Abstract
Introduction: Challenge of guinea-pig tracheal epithelium with hyperosmolar solution alters ion transport and evokes the release of epithelium-derived relaxing factor (EpDRF). Cultured tracheal epithelial cells (CE) offer the potential to examine biochemical pathways related to EpDRF release, but whether the bioelectric properties and responses of fresh, adherent epithelial cells (FE) are modeled by CE has not been established. Methods: Tracheal epithelial cells grown in air-interface culture and fresh tracheal segments were mounted in Ussing chambers to determine short circuit current (Isc) and transepithelial resistance (Rt) and to compare responses to transport inhibitors, methacholine and hyperosmolarity. Results: Significant differences in basal Isc and Rt between FE and CE were observed (Isc, 41.3 3.5 and 8.5 0.8 A/cm2, P < 0.05; Rt, 106 7 and 422 4 O cm2, P < 0.05; respectively); basal spontaneous potential difference values were not different (4.2 0.3 and 3.4 0.3 mV, respectively). Amiloride (mucosal, 3 10- 5 M), bumetanide (basolateral, 10- 5 M) and ouabain (basolateral, 10- 5 M) reduced Isc equally in FE and CE. In contrast, NPPB (10- 5 M) in the presence of amiloride had a differential effect, decreasing Isc by 11% in FE and 71% in CE (P < 0.05). Iberiotoxin (basolateral, 10- 7 M) was without effect in either preparation. In FE, serosal methacholine (3 10- 5 M) elicited an NPPB-insensitive monotonic increase in Isc, but in CE caused a large, transient, NPPB-inhibitable increase which was followed by an NPPB-resistant plateau. Addition of apical d-mannitol (0.3-267 mosM) to increase osmolarity decreased Isc in FE, whereas in CE d-mannitol initially increased (0.3-84.3 mosM) and then decreased (84.3-267 mosM) Isc. Discussion: Cell culture causes substantial changes in the bioelectric and pharmacological properties of respiratory epithelium. Caution should be exercised when using CE as a substitute for FE in studies of ion transport- and cell volume-dependent processes.
Keywords
In-vitro-studies; Lung-tissue; Lung-cells; Immunology; Immunochemistry; Immune-reaction; Cell-function; Cell-biology; Cellular-reactions; Cellular-function; Pulmonary-system
Contact
Immunobiology Branch, Research Institute, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
CODEN
JPTMEZ
Publication Date
20070301
Document Type
Journal Article
Email Address
jsf2@cdc.gov
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
2
ISSN
1056-8719
NIOSH Division
HELD
Source Name
Journal of Pharmacological and Toxicological Methods
State
WV; NC
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