Lung inflammation following a single exposure to swine barn air

Sprague-Dawley rats were exposed either to the barn or ambient air for eight hours and were euthanized at various time intervals to collect blood, broncho-alveolar lavage fluid (BALF) and lung tissue. Subsequently, following an eight hour barn or ambient air exposure, rats were challenged either with Escherichia coli (E. coli) lipopolysaccharide (LPS) or saline and euthanized 6 hours post-LPS or saline treatment. We used ANOVA (P < 0.05 means significant) to compare group differences.An eight-hour exposure to barn air induced acute lung inflammation with recruitment of granulocytes and PIMMs. Granulocyte and PIMM numbers peaked at one and 48 hour post-exposure, respectively.Secondary challenge with E. coli LPS at 48 hour following barn exposure resulted in intense lung inflammation, greater numbers of granulocytes, increased number of cells positive for TNF-α and decreased amounts of TGF-β2 in lung tissues. We also localized TNF-α, IL-1β and TGF-β2 in PIMMs.A single exposure to barn air induces lung inflammation with recruitment of PIMMs and granulocytes. Recruited PIMMs may be linked to more robust lung inflammation in barn-exposed rats exposed to LPS. These data may have implications of workers exposed to the barn air who may encounter secondary microbial challenge.Swine production is a major agricultural business in North America [1-3]. These days thousands of pigs are raised in large confinement buildings compared to small-scale family-managed operations in the past. Modern pig production operations increasingly employ full-time workers who might spend up to 8 hours/day inside the barn compared to 1–2 hours of work on the small farm in the past [4-6]. Although the environment inside these confinement buildings appears to be clean, it contains high levels of endotoxins, dust, bacterial DNA and gases such as ammonia and hydrogen sulfide [7-9].There are evidences for reduced forced expiratory volume in one second (FEV1), wheeze and increased airway hyperresponsiven