RESUMO
AIMS: Acute lung inflammation, particularly acute respiratory distress syndrome (ARDS), is caused by a variety of pathogens including bacteria and viruses. ß-Glucans have been reported to possess both anti-inflammatory and immunomodulatory properties. The current study evaluated the therapeutic effect of ß-glucans on polyinosinic:polycytidylic acid (Poly(I:C)) induced lung inflammation in both hamster and mice models. MAIN METHODS: Poly(I:C)-induced ALI/inflammation models were developed in hamsters (2.5 mg/kg) and mice (2 mg/kg) by delivering the Poly(I:C) intratracheally, and followed with and without ß-glucan administration. After treatment, lung mechanics were assessed and lung tissues were isolated and analyzed for mRNA/protein expression, and histopathological examinations. KEY FINDINGS: Poly(I:C) administration, caused a significant elevation of inflammatory marker's expression in lung tissues and showed abnormal lung mechanics in mice and hamsters. Interestingly, treatment with ß-glucan significantly (p < 0.001) reversed the Poly(I:C)-induced inflammatory events and inflammatory markers expression in both mRNA (IL-6, IL-1ß, TNF-α, CCL2 and CCL7) and protein levels (TNF-α, CD68, myeloperoxidase, neutrophil elastase, MUC-5Ac and iNOS). Lung functional assays revealed that ß-glucan treatment significantly improved lung mechanics. Histopathological analysis showed that ß-glucan treatment significantly attenuated the Poly(I:C) induced inflammatory cell infiltration, injury and goblet cell population in lung tissues. Consistent with these findings, ß-glucan treatment markedly reduced the number of neutrophils and macrophages in lung tissues. Our findings further demonstrated that ß-glucan could reduce inflammation by suppressing the MAPK pathway. SIGNIFICANCE: These results suggested that ß-glucan may attenuate the pathogenic effects of Poly(I:C)-induced ALI/ARDS via modulating the MAPK pathway, indicating ß-glucan as a possible therapeutic agent for the treatment of viral-pulmonary inflammation/injury.