Differential gene expression of proinflammatory chemokines and cytokines in lungs of ascites-resistant and -susceptible broiler chickens following intravenous cellulose microparticle injection.

Intravenous injection of microparticles (MPs) is a tool to reveal susceptibility to pulmonary hypertension (PH) syndrome (PHS, ascites) in broilers. After injection MPs get lodged in pulmonary arterioles and cause localized inflammation. To examine the expression of chemokines/cytokines during the MP-induced pulmonary inflammatory response, lungs were collected from 4-week-old broilers (6/line/time point) from the PHS-resistant (RES) and -susceptible (SUS) broilers before (0h) and after (2, 6, 12, 24, and 48h) MP injection and analyzed using quantitative RT-PCR. In both lines, expression of interleukin-1beta (IL-1beta), IL-6, IL-8, and K60 increased from 0 to 6h, reached peak levels at 6 and 12h, and decreased thereafter, whereas IL-4 and interferon gamma (IFN-gamma) expression remained elevated past 12h. Lungs from the RES line broilers had higher expression (P<0.05) of IL-1beta and IL-6 at 2, 6, and 12h; higher IL-8 at 6 and 12h; higher K60 at 6, 12, and 24h; higher IL-4 at 12, 24, and 48h and higher IFN-gamma expression at 6 and 48h post-MP injection than SUS line broilers. Higher expression of chemokines/cytokines in RES compared to SUS line lungs may explain the ability of RES line broilers to effectively counteract the MP-induced PH and resolve the vascular occlusion. Copyright 2009 Elsevier B.V. All rights reserved.