Vitamin E isoform γ-tocotrienol alleviates cigarette smoke-induced chronic obstructive pulmonary disease

OBJECTIVE Cigarette smoke-induced chronic obstructive pulmonary disease(COPD)is a leading cause of death,where inflammation and oxidative stress are involved in the pathogenesis.Vitamin E isoformγ-tocotrienol possesses both anti-oxidative and anti-inflammatory properties.We hypothesized thatγ-tocotrienol may have protective effects against COPD.METHODS BALB/c mice were exposedto cigarette smoke daily for 2 weeks with oralγ-tocotrienol treatment in the second week.Bronchoalveolar lavage(BAL)fluid was assessed for total and differential cell counts,oxidative damage biomarkers,and cytokine levels.Lung tissues were examined for the expression of antioxidants and pro-inflammatory biomarkers.In order to measure changes in lung functions in COPD,another set of mice was exposed to cigarette smoke for 2 months with oralγ-tocotrienol treatment in the last 2 weeks.RESULTSγ-Tocotrienol dose-dependently abated cigarette smoke-induced elevation of BAL fluid total and neutrophil cell counts,cytokine and chemokine(IL-1β,IL-6,IL-17,LIX,G-CSF,KC,RANTES and VEGF)levels,as well as oxidative/nitrosative damage biomarker(advanced oxidation of protein products,8-isoprostane,8-hydroxy-2-deoxyguanosine and 3-nitrotyrosine)levels.γ-Tocotrienol promoted total lung antioxidant capacity and endogenous antioxidant activities of superoxide dismutase,catalase and glutathione peroxidase.More importantly,γ-tocotrienol markedly restored work of breathing and lung functions(total lung capacity,static compliance and FEV100/FVC)in chronic experimental COPD.Furthermore,γ-tocotrienol demonstrated better anti-oxidative,anti-inflammatory,and restoration of lung functions in COPD than prednisolone.CONCLUSION We have shown for the first time the efficacy of vitamin E isomerγ-tocotrienol in protection against cigarette smoke-induced COPD by direct neutralization of free radicals,abating oxidative damage,and restoring antioxidants activities,coupled with anti-inflammatory actions in the inflamed airways.

Andrographolide restores steroid sensitivity to block LPS/IFNγ-induced IL-27 and airway hyper-responsiveness in mice

OBJECTIVE Steroid-resistant airway hyper-responsiveness(AHR)has been proposed to be related to the activation of innate host defense pathways such as those induced by LPS,IFN-γ,and LPS/IFN-γ-stimulated essential mediator IL-27.We investigated whether andrographolide,apreviously demonstrated anti-inflammatory bioactive molecule extracted from the plant Andrographis paniculata,could restore steroid sensitivity to block LPS/IFN-γ-induced IL-27 production and AHR viaits anti-oxidative property.METHODS Mouse macrophage cell line Raw264.7,mouse primary pulmonary monocyte/macrophage,and BALB/c mouse were treated with LPS/IFN-γ,in the presence and absence of increasing doses of dexamethasone and/or andrographolide.mRNA and protein levels of IL-27 in vitro and in vivo were examined,and mouse AHR was assessed.RESULTS Dexamethasone alone failed to inhibit LPS/IFN-γ-induced IL-27 and AHR in mice.Andrographolide significantly facilitated the suppressive effect of dexamethasone on LPS/IFN-γ-induced IL-27 level in macrophage cell line and primary monocyte/macrophage,mouse bronchoalveolar lavage fluid and lung tissue,and furthermore on the incurring AHR.LPS/IFN-γdid not impede nuclear translocation of glucocorticoid receptors but diminishthe protein level of histone deacetylase-2(HDAC2),an essential epigenetic enzymeresponsible for steroid anti-inflammatory action.Andrographolide at low doses(5μmol·L-1 in vitro;1mg·kg-1,ip in vivo)restored nuclear HDAC2 protein levels both in cells and in mouse lungs,possibly via suppression of PI3K/Akt signaling pathway and up-regulation of the anti-oxidative transcription factor Nrf-2level.CONCLUSION Our data suggest that andrographolide may resensitize steroid action on blocking LPS/IFN-γ-induced IL-27 and resultant AHR by restoring HDAC2 level.