Effects of Various Body Temperatures After Lipopolysaccharide-Induced Lung Injury in Rats
Study objectives: In this study, we determined the effects of various body temperatures (BTs) after initiation of lipopolysaccharide (LPS)-induced lung injury. Design and setting: Forty-nine, adult, male, Sprague-Dawley rats each weighing 300 to 400 g were used Methods: The treated rats were challen...
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Published in | Chest Vol. 128; no. 1; p. 327 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
American College of Chest Physicians
01.07.2005
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Online Access | Get full text |
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Summary: | Study objectives: In this study, we determined the effects of various body temperatures (BTs) after initiation of lipopolysaccharide (LPS)-induced
lung injury.
Design and setting: Forty-nine, adult, male, Sprague-Dawley rats each weighing 300 to 400 g were used
Methods: The treated rats were challenged with intraperitoneal (IP) administration of 5 mg/kg LPS. Control animals received IP saline
solution injections. After 16 h, treated and control animals were anesthetized. The animals received direct intratracheal
(IT) injection of LPS (1 mg/0.2 mL) or saline solution (control animals). A cooling or heating blanket was then used to control
BT. The rats were randomly assigned to three control groups of mild hypothermia (34°C) plus saline solution, normothermia
(37°C) plus saline solution, and mild hyperthermia (39°C) plus saline solution, and three LPS groups of mild hypothermia plus
LPS, normothermia plus LPS, and mild hyperthermia plus LPS, where each condition was maintained for 5 h. The mean arterial
pressure (MAP) and blood gas concentrations were measured. BAL was done in the left lung 5 h after the IT injection of LPS
with temperature control. Parts of the right lung were excised for myeloperoxidase (MPO) and malondialdehyde (MDA) measurements,
whereas the rest was collected for wet/dry (W/D) ratio determination.
Results: Normothermia plus LPS caused significantly increased W/D ratio, LDH activities, protein concentrations, and tumor necrosis
factor-α concentrations in BAL fluid, and MPO activities and MDA levels in lung tissues when compared to saline solution control
group. MAP and Pa o 2 were significantly decreased. The pathologic picture also showed increased neutrophil infiltration in lung tissues. In contrast,
treatment with mild hypothermia but not hyperthermia significantly attenuated these parameters when compared with the normothermia-plus-LPS
group.
Conclusions: These experimental data suggest that mild hypothermia applied after initiation of acute lung injury induced by LPS in rats
had a protective effect by inhibiting the inflammatory reaction. |
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ISSN: | 0012-3692 1931-3543 |
DOI: | 10.1378/chest.128.1.327 |