Biochemical changes in respiratory tissues of rats exposed to ethyl tert-butyl ether
Broadwell, KM; Schatz, R
HERO ID
1248059
Reference Type
Meetings & Symposia
Subtype
Abstract
Year
2004
Language
English
| HERO ID | 1248059 |
|---|---|
| Year | 2004 |
| Title | Biochemical changes in respiratory tissues of rats exposed to ethyl tert-butyl ether |
| Authors | Broadwell, KM; Schatz, R |
| Abstract | Ethyl tert-butyl ether (ETBE), a fuel oxygenate, is added to gasoline to improve combustion and reduce automobile emissions. Studies assessing ETBE respiratory effects are limited. Analysis of bronchoalveolar lavage fluid (BALF) and nasal lavage fluid (NLF) are sensitive tools in assessing suspected respiratory toxicants. In this study, rats were exposed to ETBE (500 and 250 ppm for 6 hours) and sacrificed both immediately and 24 hours following exposure. Significant increases in sialic acid (SA) (93%) and lactate dehydrogenase (LDH) (162%) were seen in NLF of rats sacrificed 24 hours post-exposure to 500 ppm ETBE. Significant increases were observed in protein content (101% and 174%) and acid phosphatase (ACP) (31% and 117%) at 0 and 24 h post exposure in NLF, respectively. There were significant increases in LDH activity (98%), gamma-glutamyl transferase (GGT) (149%), and ACP (86%) at 24 h post-exposure in BALF following a 500 ppm exposure. Following exposure to 250 ppm, there were significant increases in SA (46%), LDH (78%), and ACP (89%) 24 h post-exposure in NLF. ETBE is metabolized to acetaldehyde, a known respiratory irritant and free radical inducer. In vitro incubation with acetaldehyde (0.1mM -1mM) with liver, lung, and nasal mucosa microsomes was investigated in a reactive oxygen species (ROS) assay. Acetaldehyde addition produced dose-dependent increases in ROS formation in hepatic, pulmonary, and nasal microsomes (maximal values of 153%, 154%, and 217% for each organ system, respectively). Following an in vivo exposure to ETBE, there was a significant increase in ROS formation in lung microsomes (172% at 500 ppm) and nasal mucosa microsomes (181% and 140 % at 500 and 250 ppm, respectively) immediately following exposure. Biochemical changes in lavage fluid parameters indicate that ETBE is a respiratory toxicant. A possible mechanism of toxicity may be bioactivation of ETBE in target organs and subsequent formation of ROS. |
| Material Type | Abstract |
| Dupe Override | No |
| Conference Location | Baltimore, MD, USA |
| Conference Name | Society of Toxicology 43rd Annual Meeting |
| Is Public | Yes |
| Language Text | English |