| ObjectiveBalb/c mice were subjected with a single large dose of X-ray irradiation of chest,the relationships between gelsolin changes of plasma and lung tissues and theradiation-induced acute lung injury were investigated. To construct a model of lowgelsolin expression in micro-circulation or high gelsolin expression in lung tissue,detect some biochemical indicators such as MDA, SOD, TNF-α and IL-6and toevaluate the protect effects of gelsolin on radiation-induce acute lung injury.Methods1. Balb/c mice were given a single20Gy dose of X-ray irradiation of the chest, andGSN expression was observed in lung tissue by immunohistochemistry. Plasma,bronchoalveolar lavage fluid (BALF) and lung tissue were collected at different timepoints after irradiation. we observed changes of the expression and content of gelsolinin plasma, BALF and lung tissue by ELISA, western Blot and RT-PCR.2. Mice were intravenously injected with50μg GSN antibody0.5hour before20Gy of thoracic irradiation. Mice were randomly divided into three groups: irradiation(none), irradiation+IgG (IgG) and irradiation+anti-gelsolin antibodies (anti-GSN).Plasma, BALF and lung tissue were collected at different time points after irradiation.The cells in BALF were smeared and stained by Wright-Giemsa. Leukocytes numbersand total protein concentration in the BALF were detected respectively. We observedlung histopathology by light microscopy and detected the content of SOD, MDA inplasma and BALF by WST-1and TBA.3. Firstly we constructed a recombinant lentivirus vector expressing gelsolin, thengave mice lentivirus by intratracheal instillation and ten days later the mice werereceived20Gy of chest irradiation. Mice were randomly divided into three groups: irradiation+saline (saline), irradiation+Lenti-GFP (Lenti-GFP) and irradiation+Lenti-GSN (Lenti-GSN). Mice weighed daily, and plasma、BALF and lung tissue werecollected at different time points after irradiation. We verified the high expression ofgelsolin in plasma and lung tissue by ELSA and Western blot, detected leukocytesnumbers and total protein concentration in the BALF, observed lung histopathology bylight microscopy, and detected some biochemical indicators such as MDA, SOD,TNF-α and IL-6.Results1. Immunohistochemistry showed gelsolin widely distributed in the epithelial cellsof the lung. Mice were subjected to20Gy of chest irradiation. Gelsolin levels weresignificantly declined within72hours after irradiation, and gradually recovered to thebasal levels after120hours. While gelsolin concentration in the BAL fluid was slightlyincreased within120hours. Gelsolin mRNA and protein abundance in the lung declinedsignificantly after irradiation, peaked at24hour, and then started to increase after48hours.2. Numbers of leukocytes and protein concentration in BALF were significantlyhigher in irradiated mice injected with gelsolin antibody as compared with that of miceinjected with control IgG (P<0.05or P<0.01). Histological examination of lung sectionsrevealed more vascular congestion, alveolar hemorrhage and leukocytes infiltration inmice injected with gelsolin, compared with that of mice treated with control IgG. Threedays after thoracic irradiation, SOD activity was less, and MDA concentration washigher in plasma and BALF in irradiated mice injected with anti-GSN antibody ascompared with injection with control IgG (P<0.05or P<0.01).3. we successfully constructed a recombinant lentivirus vector expressing gelsolin,then gave mice lentivirus by intratracheal instillation. Ten days later, samples werecollected and mice received20Gy of chest irradiation. Flag tagged protein of the lungwere shown in mice received recombinant lentivirus, while the other were not shown.Gelsolin protein content in the lung were higher in un-irradiated mice but were lower at1day after irradiation in mice received recombinant lentivirus compared control(P<0.05). Gelsolin content in plasma were significantly higher at1day after irradiation in mice received recombinant lentivirus (P<0.01). The weight were higher in60daysafter irradiation in mice received recombinant lentivirus (P<0.05). MPO content in lung,the numbers of leukocytes and protein concentration in BALF at15,30days afterirradiation were significantly lower in mice received recombinant lentivirus (P<0.05orP<0.01). Histological examination of lung sections revealed less vascular congestion,alveolar hemorrhage and leukocytes infiltration in mice received recombinant lentiviruscompared control. At15days after thoracic irradiation, SOD activity was higher, andMDA concentration was less in plasma in mice received recombinant lentivirus(P<0.05). TNF-α and IL-6content in plasma were significantly less at60days afterirradiation in mice received recombinant lentivirus compared control (P<0.01).Conclusion1. Mice were subjected to20Gy of chest irradiation, and a mice model ofradiation-induced acute lung injury was successfully established. There is atime-dependent relationship between gelsolin expression in plasma, BALF and lungtissues and radiation-induced lung injury.2. Our study successfully established a mice model of low gelsolin expression inmicro-circulation. Inflammation and pulmonary vascular permeability were increased inthe model in which reduced the capacity of eliminating free radicals.3. We successfully established a mice model of high gelsolin expression in lungtissues. Inflammation and pulmonary vascular permeability were decreased in the modelin which improved the capacity of eliminating free radicals and inflammatory cytokines. |
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