VEGF-A , IL-8 and TNF-α mRNA relative expression (LSmean ± S.E.M) in equine monocytes 1, 2 and 4 hours after stimulation with a hay dust suspension. Alternatively, cells were treated with noscapine (150 μM) one hour before stimulation with the hay dust suspension. The relative expression is normalized to the geometric mean of reference genes. This experiment is representative of three similar experiments. (*P < 0.05).