Abstract: Objective To explore the effect of Bosentan on the expression of fibrotic related growth factors of myocardial tissue in diabetic mice． Methods Male 6-week old C57BL/6 mice were divided into 3 groups: control group, diabetes mellitus (DM) group and DM-B group (diabetes with bosentan group), 15 in each group． Streptozotocin (STZ) was injected intraperitoneally accounting for 70 mg/kg for single dose which was used to confirm that diabetes was induced in the mice, fasting blood glucose (FBG) was measured at 0-, 1-, 2-week after STZ injection． The second day after STZ injection, mice in DM-B group underwent intragastric administration of Bosentan (100 mg/kg), mice in the rest of the two groups were injected with the same amount of saline lavage for 16 weeks． RT-PCR was applied to detect transforming growth factor beta (TGF-β), connective tissue growth factor (CTGF), vascular endothelial growth factor (VEGF) and the expression of RNA (mRNA) which was the messenger of collagen protein 1 (collagen - 1)． Results After 16 weeks, fasting blood glucose in mice of DM group and DM-B group was measured which was similar without significant differences (P> 0．05), but it was significantly higher in these two groups when compared with control group (P< 0．01)． Compared with DM group, the cardiac VEGF mRNA level in DM-B group was significantly higher (P< 0．05), and the expression of fibrotic related growth factors TGF-β, CTGF and collagen-1 was significantly lower (P< 0．05)． Conclusion These findings suggest that endothelin receptor antagonists Bosentan can reduce the expression of fibrotic related growth factors of myocardial tissue in diabetic mice．