The Study Of The Atmospheric Fine Particles’ Effect On Cytotoxicity And Airway Damage In A Typical Area

The economy in our country is growing prosperity, and the development of industrialization and urbanization is more rapidly, which caused serious pollution to the environment, besides, the thing that should arouse our attention is the air pollution has become one of the main environmental factors to damage human health. The air particulate plays an important role on human health, and pose a great threat to it, which is the focus of the atmospheric pollution research in recent years. Atmospheric fine particles, especially the particulate matter smaller than 2.5 micrometers (PM2.5) which can go directly to the alveoli of the lungs, is becoming the key issue in the study of the particle impact on human health. This study mainly investigates the atmospheric fine particles on the cytotoxicity and the role of airway damage.In this study, we use glass fiber filters to collect particulate matter with the size of 2.5 microns in Jinan, Shandong Province. We use ultrapure water ultrasonic method to extract the total PM2.5 and then dissolve them in different concentrations. The human lung epithelial cells were used as exposure models in. We use MTT assay to measure the cytotoxicity of PM2.5. The enzyme activity of lactate dehydrogenase (LDH) in cell culture medium was detected by colorimetric assay. The cell aging was measured by X-Gal staining, and the generation of reactive oxygen species was measured by DCFH-DA probe. At the same time, in this study, Wistar rats were randomly divided into four groups, each group has six rats, including one saline control group, one PM2.5 low-dose treatment group(2.5mg/kg), one PM2.5 middle-dose treatment group(5.0mg/kg), one PM2.5 high-dose treatment group(10.0mg/kg). Exposures were for once time, and the treatment time is 24h. The rats were sacrificed after the PM2.5 treatment 24 hours. We use left lung tissue to make the pathological slice. The number of different types of the immune cell in bronchoalveolar lavage fluid (BALF) were analyzed. In the meantime, the content of reactive oxygen species (ROS) and the change of mitochondrial membrane potential (MMP) were also be detected, to find the effect of the atmospheric fine particles’on airway damage. The results showed that:(1) Cell proliferation was affected after 24h treatment by PM2.5 with different concentrations. PM2.5 with low concentration promoted cell proliferation, and PM2.5 with high concentration inhibited cell proliferation. With the increase of PM2.5 concentration, the activity of lactic dehydrogenase (LDH) was also on the rise, and PM2.5 with a high concentration can also promote cell aging. (2) With the increase of PM2.5 concentration, the level of ROS was on the rise, this showed that high-dose PM2.5 could induce cell oxidative stress. (3) The percentage of the neutrophil in BALF was rised, and the percentage of phagocyte was declined. This showed that PM2.5 could cause the acute inflammatory reaction of the body. With the increase of PM2.5 concentration, the level of ROS was on the rise, and the MMP were in reducing. (4) Histopathological estimate of lung sections demonstrated that, the pulmonary mesenchyme in group treated by PM2.5 was incrassated. With the increase of PM2.5 concentration, the pulmonary mesenchyme and the pulmonary parenchyma showed inflammatory reaction and pathological changes.