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Respiratory Research

, 12:133

First Online: 01 December 2011Received: 01 July 2011Accepted: 07 October 2011

Abstract

BackgroundSmoking tobacco is a leading cause of chronic obstructive pulmonary disease COPD, but although the majority of COPD cases can be directly related to smoking, only a quarter of smokers actually develop the disease. A potential reason for the disparity between smoking and COPD may involve an individual-s ability to mount a protective adaptive response to cigarette smoke CS. Glutathione GSH is highly concentrated in the lung epithelial lining fluid ELF and protects against many inhaled oxidants. The changes in GSH that occur with CS are not well investigated; therefore the GSH adaptive response that occurs with a commonly utilized CS exposure was examined in mice.

MethodsMice were exposed to CS for 5 h after which they were rested in filtered air for up to 16 h. GSH levels were measured in the ELF, bronchoalveolar lavage cells, plasma, and tissues. GSH synthesis was assessed by measuring γ-glutamylcysteine ligase GCL activity in lung and liver tissue.

ResultsGSH levels in the ELF, plasma, and liver were decreased by as much as 50% during the 5 h CS exposure period whereas the lung GSH levels were unchanged. Next, the time course of rebound in GSH levels after the CS exposure was examined. CS exposure initially decreased ELF GSH levels by 50% but within 2 h GSH levels rebound to about 3 times basal levels and peaked at 16 h with a 6-fold increase and over repeat exposures were maintained at a 3-fold elevation for up to 2 months. Similar changes were observed in tissue GCL activity which is the rate limiting step in GSH synthesis. Furthermore, elevation in ELF GSH levels was not arbitrary since the CS induced GSH adaptive response after a 3d exposure period prevented GSH levels from dropping below basal levels.

ConclusionsCS exposures evoke a powerful GSH adaptive response in the lung and systemically. These data suggests there may be a sensor that sets the ELF GSH adaptive response to prevent GSH levels from dipping below basal levels. Factors that disrupt GSH adaptive responses may contribute to the pathophysiology of COPD.

AbbreviationsBALBronchoalveolar lavage

BALFBronchoalveolar lavage fluid

COPDchronic obstructive pulmonary disease

CScigarette smoke

CSEcigarette smoke extract

ELFepithelial lining fluid

GSHglutathione

Electronic supplementary materialThe online version of this article doi:10.1186-1465-9921-12-133 contains supplementary material, which is available to authorized users.

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Author: Neal S Gould - Elysia Min - Steve Gauthier - Richard J Martin - Brian J Day

Source: https://link.springer.com/







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