Sameterol Attenuates Inlfammatory Response Of Asthma And Pro-inflammatory Cytokine Secretion Of Dendritic Cell

Objective:To investigate the ovalbumin-induced asthmatic mice and the murine bonemarrow-derived dendritic cells(DCs) stimulated by the long-actingβ2agonist(salmeterol),and observe the inflammatory response of asthma and pro-inflammatory cytokine secretionof DCs.Methods:Asthmatic mice model was established via mice stimulation with ovalbumin (OVA).Fourty mice,6-8weeks of age, were randomly distributed into four groups: All mice weresensitized on days0and14by intraperitoneal injection of either PBS or OVA. Aftersensitization, animals were exposed to aerosolized PBS-only (control group),1%OVS/PBS (OVA model group),1%OVA/0.01%LPS/PBS (OVA+LPS group), or1%OVA/0.01%LPS/salmeterol/PBS (salmeterol treatment group) for40min once a day for3consecutive days (days24,25,26). On day27, the mice were killed and lungs weredivided into two parts: the left lung lobes were lavaged three times with1ml of PBS todetect the levels of interleukin-1β(IL-1β), interleukin-6(IL-6) and tumor necrosisfactor-alpha (TNF-α); the right halves were fixed by4%paraformaldehyde for histology.Hematoxylin-eosin (HE) and Alcian blue-periodic-acid Schiff (AB-PAS) were used toanalyze the effect on the airway inflammation in different groups.In vitro, cultivate C57BL/6mouse bone marrow-derived DCs using granulocytemacrophage colony-stimulating factor (GM-CSF) medium in visit, then add differentconcentrations of salmeterol at the6th days, and add exogenous LPS, collect them at thedifferent hours. Observe morphological changes of DCs, detect apoptosis of DCs, surface costimulatory molecules, CD80, CD86, CD40, CD11c+and MHC-Ⅱ molecules with flowcytometry, and analyze the function of secretion, measure cytokine IL-1β，IL-6，TNF-αlevels in supernatant using ELISA assay, and the gene levels of IL-1β，IL-6，TNF-α usingreal-time PCR.Results:(1)Salmeterol reduced peribronchial eosinophilic infiltration and hyperplasia of gobletcells as compared with the OVA+LPS group (P<0.05);(2)Levels of TNF-α,IL-6and IL-1βwere significantly lower in samples from salmeterol-treated mice as compared tomeasurements from the OVA+LPS group but were not different from those in the OVAmodel group;(3)After salmeterol intervention and LPS-stimulated to mature DCs, whichexpression of surface molecules CD80, CD86, CD40and MHC-Ⅱ are reduced;(4)Attime after3hours,Salmeterol decreases mRNA expression levels of pro-inflammatorycytokines in LPS-activated DCs; Salmeterol reduces levels of pro-inflammatory cytokinessecreted from LPS-activated DCs in vitro, especially in concentration of10-5mol/L.Conclusion:(1)Sameterol attenuates inflammatory response of asthma, especially in the BALF andthe airway inflammation;(2) By inhibiting pro-inflammatory cytokine level,Salm eterol canregulate the inflammation of asthma;(3) DCs are probably the target immune cells in theaction of salmeterol against asthma...