[The effects of inhaled carbon monoxide on lung injury in rats caused by lipopolysaccharide].
BACKGROUND
Carbon monoxide (CO) has long been considered a toxic substance. Recent studies have revealed that CO may play an important role in intercellular signaling. We hypothesized that CO modulates the inflammatory mechanisms.


METHODS
SD rats (each study group consisting of 7 animals) inhaled 250 ppm of CO one hour prior to LPS challenges. These animals were incubated for a particular period of time (four different length of time; 1, 2, 4, and 8 hours). The control group (each study group consisting of 6 animals) had been left in the room air. Both groups were instilled with LPS (1 mg) into the lungs. At the end of each period, animals were exsanguinated, broncho-alveolar lavage (BAL) and blood sampling were performed, and a part of the small intestine was harvested. PMN numbers, protein, TNF, and IL-10 concentrations in BAL fluid were measured. Plasma TNF and IL-10 were also measured. The Wet/Dry ratio of a small intestine was calculated.


RESULTS
In the CO-inhalation group, the anti-inflammatory cytokine IL-10 concentration in the BAL fluid was higher at 8 hours after LPS challenge than the counterpart of room air group (37.6 +/- 11.4 pg.ml-1 vs. 92.8 +/- 31.5 pg.ml-1, P < 0.05). W/D ratio decreased (3.29 +/- 0.2 vs. 2.94 +/- 0.06, P < 0.05).


CONCLUSIONS
These findings indicated that CO inhalation might modulate the inflammatory response to LPS. Further study is needed to prove the therapeutic role of CO inhalation without serious adverse effects.
Department of Anesthesia, Chigasaki Municipal Hospital, Chigasaki 253-0042.
Hiroshi
H
Miyazaki
Hiroshi
H
Yamada
Maria
M
Ohta
Junichi
J
Fujimoto
Toshiharu
T
Tazawa
Ichidai
I
Kudoh
D000208:Acute Disease; D000280:Administration, Inhalation; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002248:Carbon Monoxide / Q000008:administration & dosage* / Q000502:physiology; D004195:Disease Models, Animal; D018836:Inflammation Mediators / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D008070:Lipopolysaccharides; D008171:Lung Diseases / Q000139:chemically induced* / Q000378:metabolism / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D002248:Carbon Monoxide