Evaluation of lung inflammation induced by intratracheal administration of LPS in mice: comparison between MRI and histology.
OBJECTIVE
To study the in vivo effect of intratracheal administration of lipopolysaccharide (LPS) in mice by magnetic resonance imaging (MRI) and to investigate the correlation with ex vivo histological evaluation of lung inflammation and oedema.


METHODS
LPS (or phosphate buffered saline) was administered intratracheally to thirty male Balb/C mice at a concentration of 0.3 mg/ml in a total volume of 100 microl. Animals were divided into fifteen LPS-treated and fifteen control mice. MR images were acquired 24 h after challenge in freely breathing animals with standard ECG-gated Gradient-Echo (GRE) sequences and, in a limited number of animals, with ECG-gated Ultrashort-echo time (UTE) sequences. After MRI, animals were sacrificed, and lungs were fixed and processed for histological analysis of the total volume of healthy lung tissue.


RESULTS
GRE images revealed the presence of high intensity signal in lungs of LPS-treated mice that was attributable to oedema caused by alveolar inflammation. In histological slices, regions of alterations in the normal alveolar microstructure were observed that could account for MRI findings. A good correlation was observed between the volumes of lesioned tissue measured by MRI and by histology. The volume of the lesion detected by GRE sequences was lower than the volume detected by UTE sequences.


CONCLUSIONS
The effect of intratracheal administration of LPS in mice was investigated by MRI and histology. A good correlation was observed between GRE-MRI and histological findings. MR images obtained with UTE sequences appear to be more sensitive to the presence of lesions than those obtained by standard GRE acquisitions.
Conti
Giamaica
G
Department of Morphological and Biomedical Sciences, University of Verona, Strada Le Grazie 8, Verona, Italy. giamaica@univr.it
Tambalo
Stefano
S
Villetti
Gino
G
Catinella
Silvia
S
Carnini
Chiara
C
Bassani
Franco
F
Sonato
Nicolò
N
Sbarbati
Andrea
A
Marzola
Pasquina
P
D000818:Animals; D001706:Biopsy / Q000379:methods; D008070:Lipopolysaccharides; D008168:Lung / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011014:Pneumonia / Q000139:chemically induced* / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014132:Trachea / Q000187:drug effects / Q000473:pathology
D008070:Lipopolysaccharides
Am J Physiol Lung Cell Mol Physiol. 2002 Jul;283(1):L22-30
12060557
Magn Reson Med. 2004 Aug;52(2):258-68
15282807
Eur J Radiol. 2007 Dec;64(3):381-96
17931813
J Magn Reson Imaging. 2005 Jul;22(1):170-4
15971184
J Magn Reson Imaging. 2004 Dec;20(6):967-74
15558573
Trends Pharmacol Sci. 2003 Oct;24(10):550-4
14559408
J Magn Reson Imaging. 2009 Apr;29(4):977-81
19306446
Am J Physiol Lung Cell Mol Physiol. 2003 Sep;285(3):L755-61
12794002
Drugs R D. 2008;9(5):277-306
18720999
Biochem Pharmacol. 2009 Jun 15;77(12):1827-34
19428337
Magn Reson Med. 2008 Jun;59(6):1412-21
18421693
Am J Physiol Lung Cell Mol Physiol. 2002 Nov;283(5):L952-62
12376348
Lancet. 2007 Sep 1;370(9589):765-73
17765526
Br J Radiol. 2008 Aug;81(968):601-17
18628329
NMR Biomed. 2001 Aug;14(5):297-306
11477650
Am J Respir Crit Care Med. 2008 May 15;177(10):1095-102
18276941
Chest. 2000 May;117(5 Suppl 1):223S-7S
10843920
Radiology. 2008 Sep;248(3):834-43
18647843
Contrast Media Mol Imaging. 2008 Sep-Oct;3(5):173-90
18973213
Mol Imaging Biol. 2004 May-Jun;6(3):149-59
15193249
Br J Pharmacol. 2003 Sep;140(2):239-46
12970099
Anat Rec. 2001 Apr;265(2):85-100
11323771
J Magn Reson Imaging. 2007 Mar;25(3):488-94
17279537