Prevention and therapeutic effect of quercetin on radioactivity injury of mice lungs

OBJECTIVE:To investigate the protective effect of quercetin,a naturally occurring flavonoid compound,on radiation-induced lung injury and explore its possible mechanisms.METHODS:BALB/c mice were randomly assigned to 6groups and treated as follows:1)normal control group(normal saline,intravenously);2)quercetin alone(intravenously); 3)irradiation alone group(a single 10Gy dose of radiation was administered to the mice);4)high dose quercetin intervention group(a single 10Gy dose of radiation was administered to the mice;4mg/mL of Quercetin,intravenously);5)low dose quercetin intervention group(a single 10Gy dose of radiation was administered to the mice;2mg/mL of Quercetin,intravenously);6)Amie Fortin intervention group(a single 10Gy dose of radiation was administered to the mice;4mg/mL,intravenously).Quercetin was administered at two concentrations of 2and 4mg/mL and initiated 1-2weeks before irradiation and continued for 6weeks after ir- radiation.In l-8week after irradiation,lung tissues were harvested weekly for further experiments.The sections were stained with hematoxylin and eosin(HE)and examined under a light microscope by a histopathologist.The lung levels of NF-κB was analyzed by immunohistochemistry and Western blotting.RESULTS:Gross specimen observation of lung tissue in mice:the mice lung tis- sue hyperemia,swelling,effusion,elasticity in treatment group was significantly lower than that in irradiation alone group.Patho- logical changes in radiation-injured lung tissue:light microscope examination of HE slices showed that the lung tissue in irradiated mice losted their normal cord-like structure and developed extensive swelling and large fat droplets,with balloon-like changes and serious necrosis.Inflammatory cells(lymphocyte and neutrophil)infiltrations were also observed.The degree of inflammation was slightly reduced in the quercetin intervention group(P0.05).Immunohistochemistry:NF-κB protein expression decreased(1.38±0.8,1.32±0.74)and Iκb-αprotein expression(1.6±0.14,2.06±0.12)increased significantly(P0.05).Western blotting showed that comparing with irradiation along arm,in both of the quercetin intervention groups NF-κB protein expression decreased(2.04±0.16,1.89±0.13)and Iκb-αprotein expression(0.80±0.15,0.81±0.13)increased markedly(P0.05). CONCLUSION:The results suggest quercetin exhibits a protective effect on radiation induced lung injury via suppression of NF-κB signaling pathways,which may involve the inhibition of pulmonary inflammatory process.