[Role of hydrogen sulfide/cystathionine-gamma-lyase system in acute lung injury induced by lipopolysaccharide in rats].
OBJECTIVE
To explore the role of hydrogen sulfide/cystathionine-gamma-lyase (H(2)S/CSE) system in lipopolysaccharide (LPS)- induced acute lung injury (ALI) in rats and the underlying mechanisms.


METHODS
Sixty-four Sprague-Dawley (SD) rats were randomly divided into four groups: control, LPS (instilled intratracheally to induce ALI), sodium hydrosulfide (NaHS), propargylglycine (PPG). Animals were sacrificed at 4 and 8 hours (n=8) after administration of the above agents. Morphological changes in lung tissues were determined, H(2)S, nitrogen monoxide (NO) and carbon monoxide (CO) concentration in plasma were determined. Malondialdehyde (MDA) content, and myeloperoxidase (MPO), CSE, inducible nitric oxide synthase (iNOS), heme oxygenase (HO) activity of the lung were also determined. The level of P-selectin of lung tissue was measured by radioimmunoassay. Immunohistochemistry technique was performed to examine the expression of iNOS and HO-1 protein in lung tissues.


RESULTS
Severe injuries of lung tissues and raised MDA content, MPO activity and P-selectin level were observed in rats treated with LPS. LPS also led to a drop in plasma H(2)S concentration and lung CSE activity. The enzyme activity of iNOS and HO, and their protein expression, plasma NO, and CO levels increased after LPS instillation (P<0.05 or P<0.01). Pre-administration of NaHS before LPS could attenuate the changes induced by LPS. Pre-administration of PPG exacerbated the injuries induced by LPS, with increased MDA content, MPO activity, P-selectin level, the plasma NO level, lung iNOS activity and its protein expression, but there was no prominent variation in CO level, HO activity and HO-1 protein expression compared with those of LPS group.


CONCLUSIONS
Downregulation of H(2)S/CSE is involved in the pathogenesis of ALI induced by LPS. Endogenous and exogenous H(2)S provide protection against ALI, which may be explained by its anti-oxidative effects, attenuation of inflammatory over-reaction in lung induced by polymorphonuclear neutrophils, downregulation of NO/iNOS system and the upregulation of CO/HO-1 system.
Department of Pathophysiology, Hebei Medical University, Shijiazhuang 050017, Hebei, China.
Xiao-hong
XH
Zhou
Xin-li
XL
Huang
Peng
P
Wei
Feng-jun
FJ
Tian
Yi-ling
YL
Ling
D055371:Acute Lung Injury / Q000139:chemically induced / Q000378:metabolism*; D000818:Animals; D002248:Carbon Monoxide / Q000097:blood / Q000378:metabolism; D003542:Cystathionine gamma-Lyase / Q000378:metabolism*; D004195:Disease Models, Animal; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000097:blood / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D009569:Nitric Oxide / Q000097:blood; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D019007:P-Selectin / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
D008070:Lipopolysaccharides; D019007:P-Selectin; D009569:Nitric Oxide; D008315:Malondialdehyde; D002248:Carbon Monoxide; D009195:Peroxidase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; D003542:Cystathionine gamma-Lyase; D006862:Hydrogen Sulfide