Exogenous porcine surfactants increase the infiltration of leukocytes in the lung of rats.
BACKGROUND
Several studies have investigated the influence of exogenous surfactants on inflammatory response in the lung, however results reported about effects of surfactants on the lung infiltration of leukocytes are controversial. Our previous study noticed that treatment of porcine surfactant (PS) significantly increased the lung infiltration of leukocytes in rats with acute lung injury (ALI). The objective of this study was to verify the effect of exogenous PS on the lung infiltration of leukocytes in vivo and investigate the possible mechanisms involved in vitro.


METHODS
The number of leukocytes in bronchoalveolar lavage fluid (BALF) of rats with or without lipopolysaccharide (LPS)-induced ALI was determined after treatment with different concentrations of PS, dexamethasone (Dex) or PS + Dex. The effect of PS and Curosurf, a commercially available porcine surfactant, on human peripheral neutrophil migration was determined by the Boyden Chamber Assay.


RESULTS
Instillation of PS significantly increased the number of leukocytes in BALF of normal rats and rats with LPS-induced ALI. Most of the increased leukocytes were neutrophils. Dex significantly decreased the number of leukocytes and TNF-alpha concentration in BALF caused by LPS, but did not significantly reduce the number of leukocytes increased by PS. In vitro experiments further demonstrated that both PS and Curosurf had direct chemotactic effects on neutrophils.


CONCLUSIONS
These results suggest that PS contain chemoattractant(s) which induce the infiltration of leukocytes, especially neutrophils, into lung.
Sun
Yu
Y
Department of Pathophysiology, College of Basic Medical Sciences, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
Wang
Yi-Qun
YQ
Yang
Rui
R
Zhu
Jing-Jing
JJ
Le
Ying-Ying
YY
Zhong
Ji-Gen
JG
Lu
Jian
J
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology; D007962:Leukocytes / Q000187:drug effects*; D008070:Lipopolysaccharides; D008168:Lung / Q000166:cytology* / Q000187:drug effects; D008297:Male; D020556:Neutrophil Infiltration / Q000187:drug effects; D011663:Pulmonary Surfactants / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine
D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D011663:Pulmonary Surfactants; D003907:Dexamethasone