[Research on the Anti-Pulmonary Fibrosis Effect of the Bletilla striata Polysaccharide in Rat Silicosis Model].

To investigate the anti-pulmonary fibrosis effect and the possible molecular mechanism of the Bletilla striata polysaccharide.Polysaccharide was prepared by water reflux extraction plus ethanol precipitation method, and following deproteinization process by Sevage method. Rat silicosis model was established by invasive intratracheal instillation method. The effect and molecular mechanism of the polysaccharide was evaluated by lung indexes, lung pathological change, serum levels of SOD,MDA,NF-κB,IL-1β,PDGF,TGF-β1,TNF-α,HYP were detected, and the contents of CD3~+,CD4~+,CD8~+T lymph cells and CD4~+/ CD8~+ratio were detected by flow cytometry.Both low( 100 mg / kg) and high( 400 mg / kg) dosage polysaccharide treatment could remarkably elevate the serum SOD level and reduce the MDA,NO level, and effectively reverse the CD4~+/ CD8~+ratio comparing with the model group( P < 0. 01). Except the TNF-α level was significantly lower in the high dosage treatment group, there was no other effect in inflammatory cytokines and HYP content in serum. HE pathological section confirmed that the Bletilla striata polysaccharide treatment group can not effectively prevent lung fibrosis.The Bletilla striata polysaccharide has remarkable regulation effect on antioxidation system and immune system, but can not effectively prevent lung fibrosis, more effort should be made to study the active antipulmonary fibrosis components of Bletilla striata.