[Time course of TGF beta 1 and VEGF expression in experimental vein grafts].

OBJECTIVE: To investigate time course of TGF beta(1) and VEGF expression and their role in intimal hyperplasia. METHODS: In situ hybridization and immunohistochemical technique were used to detect the time course of intimal hyperplasia, time course of TGF beta(1) mRNA and protein expression of TGF beta(1) and VEGF. RESULTS: After autogenous vein replacement, the obvious neointima was seen at 2 weeks, and peaked at 8 weeks. The expression of TGF beta(1) mRNA peaked at 1 week and decreased gradually, but at 10 weeks, its positive cell percentage was still 10.1%. Both protein expression of TGF beta(1) and VEGF in VSMCs increased from 24 hours after grafting and peaked at 2 weeks. Their positive cell percentages were 40.6% and 36.6% respectively. After 4 weeks, their expression decreased at 8 weeks, the positive cell percentages were 8.9% and 13.8% respectively. CONCLUSIONS: TGF beta(1) plays an important part in ECM accumulation by promoting ECM synthesis and decreasing ECM degradation. VEGF plays the key role in reendothelialization. They may affect each other and cooperated in the formation of intimal hyperplasia.