The effect of rock salt aerosol on the prevention of silicosis in rats / 中国职业医学

ABSTRACT

OBJECTIVE: To investigate the preventive effect of rock salt aerosol on the development of silicosis in rats. METHODS: The specific pathogen free adult male SD rats were randomly divided into normal control group, rock salt control group, silicosis model group and rock salt intervention group, 18 rats in each group. Rats in the silicosis model group and the salt rock intervention group were treated with silica dust at the concentration of 2 000.0 mg/m~3 by dynamic dusting method for 3 hours daily. Rats in the rock salt control group and the rock salt intervention group inhaled the rock salt aerosols with the mass concentration of 20.0 mg/m~3 for 30 minutes daily. The normal control group was not treated with the dust or rock salt aerosol. At the time points of 14, 28 and 56 days after exposure to dust or rock salt aerosol, 6 rats were randomly selected from each group and samples were collected. The pathological change of lung was observed, the total cell count in the bronchoalveolar lavage fluid(BALF) was performed, the enzyme-linked immunosorbent assay was used to detect the change of transforming growth factor-β(TGF-β) in BALF, surfactant D(SP-D) and superoxide dismutase(SOD) in lung tissue. RESULTS: The results of hematoxylin-eosin and Masson staining showed that the inflammatory changes of lung tissue and the pulmonary interstitial fibrosis in the rock salt intervention group were less severer than that in the silicosis model group. At 14, 28, and 56 days after dust exposure, the total cell counts in BALF and SP-D levels in lung tissue of rats in silicosis model group and rock salt intervention group were higher(P<0.05), the SOD activities in lung tissue were lower(P<0.05), as well as the TGF-β levels in BALF in silicosis model group were higher(P<0.05),compared with the normal control group and rock salt control group. The total cell counts and TGF-β levels in BALF, and SP-D levels in lung tissue of rock salt intervention group were lower(P<0.05), the SOD activities in lung tissue were higher(P<0.05), compared with the silicosis model group. CONCLUSION: Rock salt aerosol intervention may delay the pathogenesis of silicosis by improving the inflammatory response, regulating oxidative stress and reducing interstitial fibrosis of lungs.