Effects of interleukin-18 on diaphragm muscle contraction on rats.
To evaluate the role of interleukin (IL)-18 in endotoxin-induced diaphragm muscle deterioration, we studied three treatment groups, namely, a saline+endotoxin group, an IL-18+endotoxin group and an IL-18 only group using Wistar rats. Five minutes after saline or IL-18 (0.25 microg) injection, E. coli endotoxin (30 mg/kg) was injected intraperitoneally. In the saline+endotoxin group, the force-frequency curves by ANOVA (p < 0.01), twitch tension (TT) and slope during contraction time (TT/CT) were significantly lower at 4 hours than those at 0 hours due to endotoxin (p < 0.01 and p < 0.05, respectively) and nitric oxide (NO) production had increased at 4 hours as shown by NADPH diaphorase staining. In the IL-18+endotoxin group, the decrement of the force-frequency curves in a higher frequency range (50-120 Hz), and the decrements of TT and TT/CT observed at 4 hours in the saline+endotoxin group were significantly prevented, and NO production was blocked at 4 hours. In the IL-18 only group, the force-frequency curves did not change except for fatigability, and NO production did not occur. It is suggested that IL-18 itself naturally blocks NO production, even when endotoxin coexists, resulting in the prevention of deterioration of diaphragm muscle contraction by endotoxin.
Sasaki
Fumiko
F
Department of Medical Technology, College of Medical Sciences, Tohoku University, Sendai, Japan.
Shindoh
Chiyohiko
C
Niwa
Toshifumi
T
Ohtaka
Tetsuya
T
Shindoh
Yuriko
Y
D000818:Animals; D046508:Culture Techniques; D003964:Diaphragm / Q000187:drug effects / Q000502:physiology; D020382:Interleukin-18 / Q000008:administration & dosage / Q000494:pharmacology*; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects*; D009252:NADPH Dehydrogenase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013194:Staining and Labeling / Q000379:methods
D020382:Interleukin-18; D009252:NADPH Dehydrogenase