Anti-fibrosis effects of polysaccharide of Prismatomeris tetrandra on silicosis rats / 中草药

ABSTRACT

Objective: To investigate the anti-fibrosis effects of polysaccharide of Prismatomeris tetrandra on the silicosis rats and the underlying mechanism. Methods: The experimental silicosis rat model was established by oropharyngeal aspiration method. Forty male adult Wistar rats were randomly divided into two groups saline group and modeling group. The experimental fibrosis of silicosis was induced by dripping 1 mL of 50 mg/mL SiO2 onto the oropharynx of rats of the modeling group. After modeling, the modeling group were randomly divided into one model group with SiO2 and three polysaccharide groups with SiO2 plus low, medium, and high dose of polysaccharide of P. tetrandra, eight rats per group. One day after modeling, rats in three polysaccharide groups were administered with the polysaccharide at a dose of 125, 250, and 500 mg/kg, respectively, daily for 56 d, meanwhile, the saline group and the model group were given the same amount of saline daily for 56 d. The rats were then sacrificed at the 56th day of the experiment and lung tissues were collected. The pathological changes and fibrosis of the lung tissues were observed by HE staining and Masson staining. Real-time quantitative PCR method was used to detect the mRNA expression of epithelial calcium adhesion protein (E-cadherin) and alpha smooth muscle actin (α-SMA) in lung tissue; Western blotting method was used to measure the levels of E-cadherin, α-SMA, and Vimentin in lung tissue. Results: There were no significant differences in body weight between groups. Compared with the saline group, the alveolar inflammation and the pulmonary fibrosis were aggravated, the lung/body coefficient was increased, the levels of α-SMA mRNA and α-SMA protein were significantly increased, the mRNA and protein expression level of E-cadherin was decreased markedly, and the level of Vimentin was increased significantly in the model group. Compared with the model group, the alveolar inflammation and the pulmonary fibrosis were alleviated, the lung/body coefficient was decreased, the levels of E-cadherin mRNA and protein were increased markedly, the levels of α-SMA mRNA and protein expression were decreased sharply, and the levels of Vimentin were decreased significantly in the polysaccharide groups. Conclusion: The polysaccharide of P. tetrandra exhibited the anti-fibrosis effects on silicosis by reducing silicosis-induced lung injury and slowing down the process of pulmonary fibrosis.