Study On Pulmonary Toxicity Of Rats Induced By PM_2.5

Air pollution can cause many environment questions including damaging ozonosphere, acid rain around the world. It can also threaten mankind health and effect ecological system. Particulate matter is the symbolic pollutant for evaluating air pollution. Increasing epidemiological studies and toxicological studies have consistently indicated that the air particles matter, especially untrafine particles(PM_2.5) are responsible for respiratory and cardiovascular morbidity and mortality, and their toxicity is closely associated with their aerodynamic diameters. But the mechanisms of effects on cells by PMS have not been elucidated yet. Nowadays, many toxicological studies are focused on the TSP and PM₁₀, few research were conducted on PM_2.5.In the study, aerosol samples of PM_2.5(particulate matter with aerodynamic diameter less than 2.5μm) from five sites were collected using a medium- volume sampler in the urban area of Lanzhou during 15.1.2005-1.3.2005(heating period);The average concentration of PM_2.5 from five sites in Lanzhou were analyzed;Wistar rats were randomly divided into five groups including blank control group , saline control group , three level of PM_2.5 (high , middle and low) groups;Three level PM_2.5 groups were instilled intratracheally with suspensions of PM_2.5. After 12 days rats were killed. In order to study pulmonary toxicity and mechanism induced by PM_2.5, bronchoalveolar lavage fluid (BALF) of all rats were later examined, including the level of acidic phosphatase (ACP), alkaline phosphatase (AKP), albumin(ALB),totalprotein(TP),lactate dehydrogenase(LDH),IgG,IgA and ACP,AKP, ALB,TB, IgG, IgA in serum, phagocytic abilities of peritoneal macrophages in BALF, pathological of lung also observed at the same time, It can provide scientific basis for controlling air pollution and protect people away from diseases.The results indicated:(l)Average concentration of PM2.5 were 0.142mg/m3 (0.059-0.309mg/m3), respectively .those concentration were more than 0.065 mg/m3, which US, EPA enacted in air quality standards of ultrafine particles. It showed that air pollution of PM 2.5 in Lanzhou is very heavy , especially during heating period;(2) In BALF the amount of ACP , AKP , ALB , TP , LDH , IgG , IgA in BALF in exposed groups were significantly higher than those in saline control, and has a dose dependent. (3)Non-specific immunity function, the phagocytic abilities of peritoneal macrophages increased after 12 days. (4) In serum the amount of ACP ,AKP ,ALB ,TP, IgG, IgA in exposed groups were higher than those in saline eontrol, and has no a dose dependent.(5)Inflammatory changes including neutrophil and monocyte , lymphocyte hyperplasia were observed on pulmonary pathological slide in a dose dependent.lt showed that PM2.5 could have acute toxic effects on rat pulmonary cells and membrane tissues ,also bring sap immune response and macosal immune response, non-specific immunity function depress to some extent.