[Effect of dust aerosol exposure on lung function and lung histopathology in rats]

To investigate the effect of dust aerosol exposure on lung function and lung histopathology in rats.

According to random number table method, 120 Wistar male rats were divided into untreated control group, treated control group and experimental group, with 40 rats in each group. Experimental group were exposed to the wind tunnel simulation of sandstorm for 5 hours in every day; the untreated control group were put in the standard living environment next to the wind tunnel; the treated control group were exposed to the same wind tunnel simulation of sandstorm for 5 hours in every day, and the speed of wind was the same as the experimental group, but excluding dust. At different time points, the lung function and electron microscopy were performed in all rats.

The level of Dynamic Compliance (Cdyn) ((0.227 ± 0.023), (0.198 ± 0.022) ml/cmH₂O, 1 cmH₂O=0.098 kPa) and forced vital capacity (FVC) ((6.24 ± 0.29), (5.59 ± 0.19) ml) were lower in the experimental group at 90 and 120 days, as compared to the untreated control group (Cdyn: (0.266 ± 0.014), (0.265 ± 0.018) ml/cmH2O; FVC: (7.15 ± 0.23), (7.17 ± 0.20) ml) and treated control group (Cdyn: (0.269 ± 0.015), (0.264 ± 0.019) ml/cmH2O; FVC: (7.14 ± 0.19), (7.15 ± 0.21) ml) (all P<0.05). At 120 days, The level of the forced expiratory flow after 50% of the FVC ((12.3 ± 2.2) ml/s) and peak expiratory flow ((25.79 ± 0.42) ml/s) were lower in the experimental group, as compared to the untreated control group ((15.9 ± 2.5), (27.99 ± 0.36) ml/s) and treated control group ((15.8 ± 2.1), (27.90 ± 0.38) ml/s) (all P<0.01). The FVC rate of 0.2 second in the experimental group was higher than that in the untreated control group and treated control group ( (85 ± 5)%, (73 ± 4)%, (73 ± 4)%, all P<0.05). The electron microscopy showed that the lung tissues had no obvious abnormalities at 30, 60, 90 and 120 days in untreated control group and treated control group. But in the experimental group, at 30 days, the endothelial cells of alveolar type I cells were swelled and the number of alveolar type II cells were increased; at 60 days, alveolar type II cells hyperplastic, basement membrane thinned and destructed; at 90 days, the number of alveolar type II cells decreased, Lamellar body evacuation; at 120 days, a lot of collagen fiber was formed in the alveolar septa.

The strong sandstorm environmental exposure to a certain period of time can cause the decline of lung function and the damage of lung histopathology in rats. Exposure time was positively correlated with the damage of lung tissue.