ABSTRACT
To investigate the effect and mechanism of intravascular brachytherapy with 192 Ir on expression of type I collagen after angioplasty. Restenosis model of domestic miniswine was employed.After angioplasty, the iliac arteries were randomized to brachytherapy group ( n =6) , which were treated with 20 25Gy of 192 Ir, and control group ( n =18). The target vessels were harvested at the 12 th week and the 24 th week after angioplasty. Immunohistochemistry and in situ hybridization were used to detect proteins of type I collagen, metalloproteinase 1 (MMP 1) and its tissue inhibitor (TIMP 1), and mRNA expression of type I collagen. The results showed that the protein and mRNA of type I collagen, and the ratios of TIMP 1/MMP 1 were lower in brachytherapy group than in control group. The peak of mRNA expression of type I collagen was at the 24 th week in control group and at the 12 th week in brachytherapy group, respectively. It suggested that intravascular brachytherapy with 192 Ir affects the metabolism of extracellular matrix by inhibiting the synthesis of type I collagen and regulating the activities of MMP 1 and TIMP 1.