Abstract:Chrysotile asbestos is a kind of asbestos that is controversial in safety, and it is of great significance to study its pathogenesis in a reasonable and feasible way to reflect its exposure process. A multiple non-exposed intratracheal instillation method was used to expose male Wistar rats under the condition of different concentrations of chrysotile asbestos. After exposure for 1, 3 and 6 months, the rats' body weight and lung coefficient were recorded, and pulmonary tissue and HE Staining slices were observed. The brochoalveolar lavage fluid (BALF) was collected to measure the change of different kinds of white cells, total protein (TP), lactate dehydrogenase (LDH), acid phosphatase (ACP) and alkaline phosphatase (AKP). The results showed that a low mortality was presented by using the multiple intratracheal instillation method. The body weight increased slowly and lung coefficient increased with the time and dosage. The edema, granuloma and atrophy appeared in pulmonary tissue. The increased inflammatory cells, destroyed alveolar and fibrosis were observed by HE staining. Chrysotile asbestos induced the increase of total white cells, the neutrophils and lymphocytes percentages, but the reduction of the macrophages percentage in BALF. The values of TP, LDH, ACP and AKP in exposure groups were higher than those in control group with a significant dose-response correlation. All these results prove that the multiple intratracheal instillation method could be used to simulate the chronic exposure of chrysotile asbestos. The Xinkang chrysotile asbestos could induce lung injury through destroying the lymphocytes, alveolar epithelial cells and alveolar epithelial-capillary barrier.