| Objective:The models of exposure to hypoxia,fine particulate matter(PM2.5),both exposure and intervention with NAC were established.We analyzed the effect of PM2.5 exposure with hypoxia on lung injury of rats and potential mechanisms and the intervention effect of NAC.Methods:36 SD rats were randomly divided into 6 groups:filter air group?FA group?,hypoxia and filter air group?H+FA group?,PM2.5 exposure group?PM group?,hypoxia and PM2.5 exposure group?H+PM group?,PM2.5 exposure and NAC group?PM+NAC group?,hypoxia with PM2.5 exposure and NAC intervened group?H+PM+NAC group?.Rats were killed after feeding for one month.We observed the pathomorphism changes of lung tissue by HE staining,detected contents of MDA,activity of CAT and T-SOD in lung tissue,detected mRNA and protein expression of Nrf-2,HO-1,NQO1 in rats'lung tissue by RT-PCR,Western Blot and immunohistochemistry.Results:1.The comparison of PM2.5 concentration between groups:PM2.5concentration in two groups was 170.33±71.91?g/m3 and 14.27±3.34?g/m3.The statistical results showed that the PM2.5 concentration in PM2.5 exposure groups was significantly higher than FA group?P<0.005?.2.The comparison of the histological manifestation of lung tissue on rats in different groups:?1?Compared with FA group,HE staining results showed that there were significant lung tissue inflammatory injuries in the H+FA group and PM group rats.Compared with H+FA group and PM group,H+PM group had an aggravated lung injury.Compared with PM group,PM+NAC group showed an attenuated lung injury.And compared with H+PM group,H+PM+NAC group showed an attenuated lung injury.HE staining of H+FA group showed thinner alveolar septum,multiple bullaes and infiltrated inflammatory cells surrounding bronchus.PM group showed thickened septum,multiple bullaes and infiltrated inflammatory cells surrounding bronchus.H+PM group showed significantly thickened septum,narrowed and decreased alveolar cavity and massive inflammatory cell infiltration surrounding bronchus.Compared with PM group,HE staining of PM+NAC group showed thickened septum and attenuated inflammatory cell infiltration.Compared with H+PM group,HE staining of H+PM+NAC group showed attenuated thickening of septum,increased alveolar cavity and number and decreased inflammatory cell infiltration surrounding bronchus.?2?The results of lung histopathologic score showed that the pathologic scores of H+FA group and PM group was significantly higher than that of FA group,H+PM group was significantly higher than H+FA group and PM group?P<0.05?.PM group was significantly higher than PM+NAC group P<0.05).Compared with H+PM+NAC group,H+PM group increased significantly?P<0.05?.3.The comparison of MDA contents:MDA contents in FA group,H+FA group,PM group,H+PM group,PM+NAC group and H+PM+NAC group were?1.92±0.33??mol/gprot,?2.82±0.17??mol/gprot,?3.18±0.16??mol/gprot,?3.78±0.68??mol/gprot,?2.60±0.99??mol/gprot,?3.36±0.80??mol/gprot?H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group was significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.005?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.4.The comparison of CAT activity:CAT activity in different groups were?12.97±0.43?U/mgprot,?14.95±0.31?U/mgprot,?14.92±1.03?U/mgprot??16.89±0.23?U/mgprot,?12.98±1.14?U/mgprot,?14.84±0.52?U/mgprot.H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group was significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.05?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.5.The comparison of T-SOD activity:T-SOD activity in different groups were?7.91±0.72?U/mgprot,?6.64±0.17?U/mgprot,?6.68±0.14?U/mgprot,?5.74±0.37?U/mgprot,?7.48±0.09?U/mgprot,?6.86±0.17?U/mgprot.FA group was significantly higher than H+FA group and PM group?P<0.005?.H+FA group and PM group were significantly higher than H+PM group?P<0.005?.PM+NAC group was significantly higher than PM group?P<0.005?.H+PM+NAC group was significantly higher than H+PM group?P<0.005?.6.The comparison of expression of Nrf2 mRNA and protein:?1?The relative expressions of Nrf2 mRNA were 1.00,1.36±0.29,1.44±0.17,1.78±0.42,1.19±0.11,1.18±0.39.H+FA group and PM group were significantly higher than FA group?P<0.05?.H+PM group were significantly higher than H+FA group and PM group?P<0.05?.PM group was significantly higher than PM+NAC group?P<0.005?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.?2?The positive expression Areas?Area?were 334137.33±9788.94,511017.67±41479.33,479417.33±66003.01,601677.33±67724.62,485669.00±58269.12,489452.33±38218.32.The integral optical densities were 108389±2072.84,304135±39699.04,229502±37623.25,445875.67±61703.96,132358.67±3571.86,315090.33±59223.37.Both Area and IOD of H+FA group and PM group were significantly higher than that of FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.05?.PM group was significantly higher than PM+NAC group?P<0.05?.H+PM group was significantly higher than H+PM+NAC group?P<0.05?.?3?The relative expressions of Nrf2 protein were 0.054±0.005,0.089±0.004,0.177±0.005,0.359±0.008,0.119±0.004,0.203±0.005.H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.005?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.7.The comparison of expression of HO-1 mRNA and protein:?1?The relative expressions of HO-1 mRNA were 1.00,2.51±0.67,2.50±0.43,4.17±0.62,1.33±0.25,2.55±0.37.H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.05?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.?2?The positive expression Areas?Area?were 517700.33±8881.38,708376.67±5862.01,678676.67±18207.98,858368±27739.89,510286.67±40983.87,385746.67±42978.43.The integral optical densities were 243760.67±23495.73,400516.00±62385.09,334375.67±30891.76,513810.00±6765.41,165453.67±7506.43,178997.33±16796.58.Both Area and IOD of H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.005?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.?3?The relative expressions of HO-1 protein were 0.010±0.001,0.019±0.006,0.050±0.001,0.133±0.011,0.033±0.002,0.064±0.004.H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.005?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.8.The comparison of expression of NQO1 mRNA and protein:?1?The relative expressions of NQO1 mRNA were 1.00,2.10±0.45,2.54±0.45,6.05±4.08,1.72±0.53,1.67±0.87.H+FA group and PM group were significantly higher than FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.05?.PM group was significantly higher than PM+NAC group?P<0.05?.H+PM group was significantly higher than H+PM+NAC group?P<0.05?.?2?The positive expression Areas?Area?were 468476.33±9554.18,582378.33±7258.87,573849±22456.64,682507.33±53714.39,448763.33±27557.35,549099.67±50044.13.Both Area and IOD of H+FA group and PM group were significantly higher than that of FA group?P<0.05?.H+PM group were significantly higher than H+FA group and PM group?P<0.05?.PM group was significantly higher than PM+NAC group?P<0.05?.H+PM group was significantly higher than H+PM+NAC group?P<0.05?.?3?The relative expressions of NQO1 protein were 0.037±0.001,0.434±0.022,0.529±0.015,0.712±0.017,0.482±0.035,0.608±0.015.H+FA group and PM group were significantly higher than that of FA group?P<0.005?.H+PM group were significantly higher than H+FA group and PM group?P<0.005?.PM group was significantly higher than PM+NAC group?P<0.05?.H+PM group was significantly higher than H+PM+NAC group?P<0.005?.Conclusions:1.Both hypoxia exposure and PM2.5 exposure can cause rats'lung injury.2.PM2.5 and hypoxia exposure may aggravate rats'lung injury.3.Hypoxia,PM2.5.5 exposure and both exposure may acticate antioxidant pathway via upregulation of Nrf2,HO-1 and NQO1.4.NAC may attenuate lung injury in rats'lung tissue induced by hypoxia with PM2.5 exposure... |
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