Effects of melatonin in the airways of an Asthma-COPD overlap model

<bold>Background:</bold> Melatonin has important effects on inflammation responses and could be a possible therapeutic target for asthma, COPD and asthma-COPD overlap (ACO). <bold>Objective:</bold> To evaluate melatonin treatment in lung hyperresponsiveness, inflammation and oxidative stress responses in models of asthma, COPD and ACO. <bold>Methods:</bold> Experimental groups: ELA: received Elastase; OVA: received ovalbumin intraperitoneally and inhalation of ovalbumin; ACO: received elastase and ovalbumin intraperitoneally and inhaled; SAL: received saline; ELA+MEL, OVA+MEL and ACO+MEL: groups were submitted to the experimental protocols previously described and melatonin for 6 days. After 28 days, we evaluated in the airway cell expression of TGF-Beta, MMP-9, MMP-12 and TIMP-1, transcription factor NF-KappaB, inflammatory markers IL-2, IL-4, IL-5, IL-6, IL-10, IL-17 and oxidative stress marker iNOS. <bold>Results:</bold> A reduction in the using immunohistochemistry of TGF-Beta, MMP-9, MMP-12, TIMP-1, NF-KappaB, IL-2, IL-4, IL-5, IL-6, IL-10, IL-17 and iNOS was observed in the treated groups compared to non-treated animals (Table 1). <bold>Conclusion:</bold> Melatonin attenuated oxidative stress and lung inflammation in these models. Probably these mechanisms depend on NF-KappaB activation. <bold>Financial Support:</bold> FAPESP (numbers 2018/02537-5, 2020/11716-0 and 2020/14255-4), CNPq, LIM-20-HC-FMUSP.