Objective We aimed to investigate whether magnetic stent has preventive effect on in-stent restenosis by observing expressions of matrix metalioproteinase (MMP)2,MMP9,tissue inhibitor of matrix metalloproteinase (TIMP)1 and TIMP2 after balloon angioplasty,bare and magnetic stent implantation in rabbits.Methods Rabbits underwent balloon angioplasty,bare and magnetic stent implantation in the left iliac arteries.The changes of MMPs and TIMPs were examined at various time points in the injured arteries using the methods of zymography,Western blot analysis,reverse transcription-polymerase chain reaction (RT-PCR) and morphometric analysis.Results Balloon angioplasty group (BA) and magnetic stent group (MS) showed lower intrinsic gelatinolytic activity and higher expression of TIMPs with less intimae hyperplasia;Whereas bare stent (BS) group exhibited higher intrinsic gelatinolytic activity and lower expression of TIMPs with significant intimae hyperplasia.Conclusion Magnetic stent probably has preventive effect on in-stent restenosis by changing intrinsic matrix metalloproteinases activity and expression of TIMPs.

Objective To investigate the preventive effect of magnetic stent on coronary restenosis after percutaneous arterial stenting.Methods Twenty rabbits were divided randomly into 2 groups.Bare stent(BS group,n=10)or magnetic stent(MS group,n=10)wasimplanted in the left iliac artery of the rabbits of the 2 groups,respectively.Aspirin (25mg,qd )was administered orally to the rabbitsof both groups from 3 days before stenting until the rabbits were executed.Unfractionated heparin (2500u,qd) was delivered subcuta-neously after stenting for 7days.Five rabbits of each group were randomly selected to be executed at 7 or 30 days.Stmctural changesin the iniured arteries were studied by optical microscopey,transmissive electronic microscopey and immunohistochemistry.ResultsAt 7 days.more myofibroblasts were found migrating from adventitia to tunica media and intima in BS group than in MS group.insidethe media and intima,large amount of smooth muscle cells of synthetic type were observed.At 30 days after stenting,in magnetic group,most uascular smooth musele cells(SMCs)under the intima had transformed to contractile type and only little extracellular matrix(ECM)was observed around the SMCs;whereas,in BS group,the SMCs remained to be synthetic type and large amount of ECM wasobserved around the SMCs.which was composed mainly of proteoglycans and glycoproteins. Conclusions Magnetic stent caninhibit proliferation and migration of SMCs and reducing the production of ECM.and therefore,may prevent restenosis after coronarystenting.

Magnesium and its alloy are used for the most potential endovascular stent material due to their excellent mechanical capabilities, adjustable corrosive properties, the little side effects of the materials and their degradation products. The in vito degradation rate of the current magnesium and its alloy as endovascular stent is very quickly so that the artery is not supported long enough to prevent negative remodeling. This review detailed the approach to enhance the corrosion resistance, in vitro corrosion rate measurement of magnesium and its alloy, as well as the in vito corrosion research when as the endovascular stents.
Alloys ; chemistry ; Biocompatible Materials ; Corrosion ; Humans ; Magnesium ; chemistry ; Materials Testing ; Stents