Objective: To study the effect of Hedysari Radix flavonoids in different time points on angiogenesis index in the pulmonary interstitial fibrosis rat model. Method: Hundred and forty-four SPF Wistar rats were distributed to blank group

model group

prednisone group

Hedysari Radix flavonoids high

middle

low dose groups by bleomycin intratracheal instillation method to establish the model of pulmonary fibrosis. From the second day after modeling

the corresponding drugs were given to each group

ig for 14 days or 28 days. Immunohistochemistry method was used to observe the expression of vascular endothelial growth factor (VEGF) and its receptor (VEGFR2). Result: Model groups 14

28 days VEGF and VEGFR2 increased significantly when compared with the control group.Compared with 14 d model group

high dose flavonoids group in VEGF and VEGFR2 expression decreased (P<0.05). Compared with 28 d model group

high dose flavonoids group in VEGF and VEGFR2 expression decreased significantly (P<0.05). Fourteen

28 d low dose groups had no significant difference with the 28 d model group

in VEGF and VEGFR2 expression. 14

28 d middle dose groups in expression of VEGF and VEGFR2 were between 14

28 d high dose group and low dose group

and had no statistical significance with 14 d

28 d model group. Conclusion: The anti fibrosis mechanism of Hedysari Radix flavonoids was probably through inhibiting angiogenesis related factor VEGF and VEGFR2 to inhibit the formation of pathological angiogenesis resulting in the delayed pulmonary fibrosis.