Effects of Endovascular Brachytherapy with ^(192)Ir Afterloading System on Expression of Type I Collagen after Angioplasty

摘要

Objectives To investigate the effect and mechanism of endovaseular braehytherapy with ^192Ir on expression of type I colla gen, metalloproteinases - 1 (MMP - 1 ) and the tissue inhibitor (TIMP-1) after angioplasty. Methods Restenotie model of domestic mieroswine was employed and the iliae arteries were randomized to radiation group (n=12), which were treated with 20 - 25Gy of ^192Ir, and non-radiation group ( n=36) after angioplasty. The target vessels were harvested in the end of 3 months and 6 months after angioplasty. Im-munohistochemistry and in situ hybridization were used to detect proteins of type I collagen, MMP- 1 and TIMP - 1, and mRNA expression of type I collagen.Results The protein and mRNA of type I collagen,the ratios of TIMP-1/MMP-1 were significantly lower in radiation group than in non- radiation group( P<0.05 or 0.01 ). The peak of transcription of type I collagen mRNA was at 6 months and 3 months in non-radiation group and radiation group respectively.Conclusions Endovascular brachytherapy with ^192Ir might modify the metabolism of extracellular matrix after angioplasty by inhibiting the synthesis of type I collagen and the activities of MMP - 1 and TIMP-1.