, 2009); however, recent studies in murine models of asthma have suggested that AE might have a possible anti-inflammatory effect on chronic allergy airway inflammation (Pastva et al., 2004, Vieira

et al., 2007, Vieira et al., 2011 and Silva et al., 2010). Our group and others have shown some effects Y-27632 mouse of AE on chronic allergic lung inflammation (Pastva et al., 2004, Vieira et al., 2007, Vieira et al., 2008, Vieira et al., 2011 and Silva et al., 2010). However, many criticisms have been raised concerning the mouse model of asthma involving the use of ovalbumin. Wenzel and Holgate (2006) suggest that mouse models of asthma provide insights into immunologic processes but have shortcomings that continue to limit the understanding and treatment of human asthma. Several reasons are given as limitations: (i) mouse models of asthma require artificial intra-peritoneal allergen sensitization and adjunctive stimulation and provoke a systematic find protocol rather than a

pulmonary allergic sensitization, which can even extend to include cardiovascular effects (Bice et al., 2000); (ii) the site of inflammation is mainly located in the parenchyma and the lung vascular vessels instead of the airways as occurs in human asthma (Wenzel and Holgate, 2006); and (iii) mice have lower levels of eosinophils in the airways following antigen challenge compared to guinea pigs and humans with asthma (Korsgren et al., 1997). Our results showed that sensitized guinea pigs submitted to AE training had a reduction in eosinophil migration as well as in the migration of lymphocytes to the airways,

which reinforced previous studies showing that AE reduces eosinophilic inflammation in mouse models of asthma (Pastva et al., 2004 and Vieira et al., 2007). However, the reduction in lymphocyte migration to the airways following AE was previously unknown and is interesting because lymphocytes orchestrate eosinophilic migration. To better understand the effect of AE on reducing eosinophilic migration, we quantified the expression of Th2 cytokines. The results show that AE reversed the OVA-induced expression of IL-4 and IL-13, suggesting an important effect of AE on the pro-inflammatory cytokines involved in Cyclooxygenase (COX) allergic airway inflammation. Despite the fact that AE has been shown to reduce IL-4 expression in mouse studies (Pastva et al., 2004, Vieira et al., 2007, Vieira et al., 2008 and Vieira et al., 2011), this is the first study in guinea pigs to show that AE can also reduce the expression of IL-13. IL-13 is an important interleukin in the pathophysiology of asthma that modulates eosinophilic inflammation and mucus hypersecretion (Zhu et al., 1999). In addition, a study by Willis-Karp et al. demonstrated that these pro-asthmatic effects of IL-13 are independent of IgE production (Wills-Karp et al., 1998).