Synchrotron microradiography study on acute lung injury of mouse caused by PM2.5 aerosols

In order to investigate FeSO4, ZnSO4 (the two of main metal compositions of Shanghai PM2.5 (particle matter with those aerodynamical diameter <2.5 μm)) effects on acute lung injury, six solutions contained PM2.5 aerosol particles, FeSO4, ZnSO4 and their mixtures were instilled intratracheally into mouse lungs for experiment. By 2 days after instillation, the live mice were checked in vivo by synchrotron refractive index microradiography. In addition after extracted and examined by dissection, the right lobes of lung were fixed by formalin, then imaged by synchrotron microradiography again. Corresponding parts of those lung tissues were embedded in paraffin for histopathologic study. The synchrotron X-ray microradiographs of live mouse lung showed different lung texture changes after instilled with different toxic solutions. Hemorrhage points in lung were observed more from those mice instilled by FeSO4 contained toxin solutions groups. Bronchial epithelial hyperplasia can be observed in ZnSO4 contained solution-instilled groups from histopathologic analysis. It was found that the acute lung injury of mice caused by solution of PM2.5 + FeSO4 + ZnSO4 was more serious than other toxin solutions. Results suggested that FeSO4 mainly induced hemorrhage and ZnSO4 mainly induced inflammation and bronchiolar epithelial hyperplasia in the early toxicological effects of PM2.5.