可降解AZ31镁合金支架在兔腹主动脉的降解性能研究

The degradation performance of AZ31 bioabsorbable magnesium alloy stent implanted in the abdominal aorta of rabbits

目的初步评价可降解AZ31镁合金支架在兔主动脉的降解性能。方法将12枚可降解AZ31镁合金支架置入12只新西兰大白兔腹主动脉中。分别于术后1个月(n=3)、2个月(n=3)、3个月(n=3)及4个月(n=3)处死动物。对支架段血管进行X线照相及病理检查。结果12只实验兔在随访期存活良好。X线照相及病理显示1个月时支架形态完整,扩张完全;2个月时支架部分支杆降解断裂,失去支撑作用;3个月时大部分支架支杆降解,4个月时所有支架完全降解。支架在兔主动脉中完全降解所需时间为104.5 d。结论可降解AZ31镁合金支架在兔主动脉中2个月内失去支撑作用,延长支撑时间是未来的研究方向。

Objective To make a preliminary evaluation of the degradation of AZ31 bioabsorbable magnesium alloy stent implanted in the abdominal aorta of experimental rabbits.Methods Twelve AZ31 biodegradable magnesium alloy stents were separately deployed in the infrarenal abdominal aortas of twelve New Zealand white rabbits.Every three experimental rabbits were sacrificed each time at one,two,three and four months after the procedure of stenting.The stenting segment of the aortas were harvested,radiographed and sent for pathologic examination to observe the degradable performance of the stent.Results All animals survived form the operation in the scheduled follow-up period.Radiographically and pathologically,the stents were fully expanded with perfect shape one month after the procedure,and part of the stent struts began to be degraded and fractured in two months,resulting in the loss of its supporting function.Three months after the implantation most stents were corroded,and in four months all the stents become completely destroyed.The estimating time for producing complete degradation of AZ31 magnesium alloy stents in rabbit’s aorta was 104.5 days.Conclusion AZ31 bioabsorbable magnesium alloy stents implanted in rabbit abdominal aorta will lose their radial force in two months.How to prolong the functioning time of the implanted stents is the next research target.