Methylene blue prevents pulmonary injury after intestinal ischemia-reperfusion.
OBJECTIVE
To investigate the effect of methylene blue, an inhibitor of oxygen radicals, on lung injury caused by reperfusion of ischemic tissue.


METHODS
Intestinal ischemia-reperfusion injury was induced in rats by clamping the superior mesenteric artery for 1 hour. Thereafter, the experimental group was administered 1% methylene blue intraperitoneally and the control group received saline. After 4 hours, pulmonary histopathologic features were assessed, and lung wet-weight to dry-weight ratios and tissue xanthine oxidase were determined.


RESULTS
The control group suffered from severe pulmonary parenchymal damage, compared with slight damage in the experimental group. The number of sequestered neutrophils was significantly higher in the control group (319 +/- 60 polymorphonuclear cells per 10 high-power fields) than in the methylene blue-treated group (91 +/- 8 polymorphonuclear cells per 10 high-power fields; p < 0.001). The wet-weight to dry-weight ratio was significantly increased in the saline-treated rats compared with the methylene blue-treated group (6.19 +/- 0.28 vs. 5.07 +/- 0.21; p < 0.001). Xanthine oxidase activity was similar in both groups.


CONCLUSIONS
Methylene blue attenuated lung injury after intestinal ischemia-reperfusion. Inhibition of oxygen free radicals may be the protective mechanism.
Galili
Y
Y
Department of Surgery B-C, Tel-Aviv Sourasky Medical Center, Israel.
Ben-Abraham
R
R
Weinbroum
A
A
Marmur
S
S
Iaina
A
A
Volman
Y
Y
Peer
G
G
Szold
O
O
Soffer
D
D
Klausner
J
J
Rabau
M
M
Kluger
Y
Y
D000818:Animals; D000975:Antioxidants / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D007422:Intestines / Q000098:blood supply*; D007958:Leukocyte Count; D008297:Male; D008751:Methylene Blue / Q000627:therapeutic use*; D009504:Neutrophils; D009929:Organ Size; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000150:complications*; D012128:Respiratory Distress Syndrome / Q000188:drug therapy* / Q000201:enzymology / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D014969:Xanthine Oxidase / Q000032:analysis
D000975:Antioxidants; D014969:Xanthine Oxidase; D008751:Methylene Blue