Abstract: Abstract Objective：To investigate the effect of saikosapoin-d（SSd）on the expression of VEGF/PEDF at different times in lung tissue of Blemycin-induced pulmonary fibrosis in mice，and to explore its relationship with　anti-fibrosis． Methods：Eighty mice were randomly divided into four groups: control group，model group and two treatment groups．After modeling，the Mice in the treatment groups were injected intraperitoneally with SSd at different doses　once per day．Lung tissue was stained with Masson method，Hydroxyproline(HYP) content was evaluated，the expressive law of VEGF and PEDF was observed by immunofluorescence， the expressive intensity of VEGF and PEDF mRNA was dectected by RT-PCR. Results：In model group and treatment groups, dynamic changes from alveolitis to pulmonary fibrosis could be observed in Masson staining; HYP levels increased gradually，and reached peak on the day of 28．The expression of VEGF in model group began to increase from the third day，reached the peak on the seventh day，then gradually decreased；the expression of PEDF presented tendency which elevates gradually．In treatment groups，the expression of VEGF was lower than in model group；the expression of PEDF mRNA in 2 SSd groups was higher than in model group． Conclusion：SSd can inhibit pulmonary fibrosis in mice, it may be related to the down-regulation of VEGF and up-regulation of PEDF, and this effect is positively related to dose.

Key words: SSd, Pulmonary fibrosis, VEGF, PEDF, Mice