Hemeoxygenase-1 upregulation is critical for sirtinol-mediated attenuation of lung injury after trauma-hemorrhage in a rodent model.
BACKGROUND
Hemeoxygenase-1 induction in response to adverse circulatory conditions is protective. Our recent study has shown that administration of sirtinol attenuates hepatic injury in male Sprague-Dawley rats after trauma-hemorrhage; however, the mechanism by which sirtinol produces the salutary effects remains unknown. We hypothesized that sirtinol administration in male Sprague-Dawley rats after trauma-hemorrhage decreases cytokine production and protects against lung injury through a hemeoxygenase-1 related pathway.


METHODS
Male Sprague-Dawley rats (n = 8 per group) underwent trauma-hemorrhage (mean arterial blood pressure 40 mm Hg for 90 min, then resuscitation). A single dose of sirtinol (1 mg/kg of body weight) with or without a hemeoxygenase enzyme inhibitor (chromium-mesoporphyrin) or vehicle was administered IV during resuscitation. Twenty-four hours thereafter, myeloperoxidase activity (a marker of neutrophil sequestration) and tumor necrosis factor alpha, interleukin-6, and interleukin-10 levels in the lung, protein concentrations in bronchoalveolar lavage fluid and tissue histology were measured. Lung hemeoxygenase-1 protein level was also determined.


RESULTS
In the sirtinol-treated rats subjected to trauma-hemorrhage, there were significant improvements in lung myeloperoxidase activity (4.68 +/- 0.31 vs 9.36 +/- 1.03 U/mg protein, P < 0.05), tumor necrosis factor alpha levels (710.7 +/- 28 vs 1288 +/- 40.69 pg/mg protein, P < 0.05), interleukin-6 levels (343.6 +/- 18.41 vs 592.7 +/- 22.3 pg/mg protein, P < 0.05), and protein concentrations (303.8 +/- 24.54 vs 569.6 +/- 34.82 microg/mL, P < 0.05) and lesser damage in histology. There was no statistically significant difference in interleukin-10 levels in the lung between sirtinol-treated trauma-hemorrhaged rats and vehicle-treated trauma-hemorrhaged rats (842.5 +/- 54.18 vs 756.2 +/- 41.34 pg/mg protein, respectively). Lung hemeoxygenase-1 protein levels were increased in rats receiving sirtinol treatment as compared with vehicle-treated trauma-hemorrhaged rats (5.18 +/- 0.25 vs 2.70 +/- 0.16, P < 0.05). Administration of the hemeoxygenase inhibitor chromium-mesoporphyrin prevented the sirtinol-induced attenuation of shock-induced lung damage.


CONCLUSIONS
The salutary effects of sirtinol administration on attenuation of lung inflammation after trauma-hemorrhage are mediated via upregulation of hemeoxygenase-1 expression.
Liu
Fu-Chao
FC
Department of Anesthesiology Chang Gung Memorial Hospital, 5 Fu-Shin Street, Kwei-Shan Tao-Yuan, Taiwan 333.
Day
Yuan-Ji
YJ
Liao
Chang-Hui
CH
Liou
Jiin-Tarng
JT
Mao
Chih-Chieh
CC
Yu
Huang-Ping
HP
D000818:Animals; D001549:Benzamides / Q000627:therapeutic use*; D015153:Blotting, Western; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D006470:Hemorrhage / Q000150:complications* / Q000473:pathology; D016753:Interleukin-10 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D008171:Lung Diseases / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D009284:Naphthols / Q000627:therapeutic use*; D009195:Peroxidase / Q000378:metabolism; D011506:Proteins / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D037761:Sirtuins / Q000037:antagonists & inhibitors*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D014947:Wounds and Injuries / Q000150:complications* / Q000473:pathology
D001549:Benzamides; D015850:Interleukin-6; D009284:Naphthols; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; C439060:sirtinol; D016753:Interleukin-10; D009195:Peroxidase; D051547:Heme Oxygenase-1; D037761:Sirtuins