Degradation of a magnesium alloy stent in the rabbit abdominal aorta / 中国组织工程研究

ABSTRACT

BACKGROUND:Foreign studies have found that the magnesium alloy stent is safe and effective, but there are few studies on the degradation performance of magnesium alloy stents in China.OBJECTIVE:To investigate the degradation of degradable AZ31 magnesium alloy stent in the rabbit abdominal aorta and the effect of degradation process on vascularization.METHODS:Twenty-eight rabbits were enrolled, and the degradable AZ31 magnesium alloy stent was implanted into the rabbit abdominal aorta. Postoperative abdominal aortic X-ray examination and histological observation were done at 30, 60, 90, 120 days after implantation.RESULTS AND CONCLUSION:(1) X-ray examination 30 days after implantation, the stent expanded completely with structural integrity; 60 days after implantation, the stent deformation, partial stent fracture, and lose of support were found; 90 days after implantation, only a small amount of support rod residues were found, and the majority of the stent was degraded; and 120 days after implantation, there was no support rod residual, and the stent was degraded completely. (2) Histological observation 60 days after implantation, the number of residual support rods was less than that 30 days after implantation (P< 0.05), the number value at 90 days after implantation was lower than that at 30 and 60 days after implantation (P< 0.05), and the number value at 120 days after implantation was lower than that at 30, 60, 90 days after implantation (P < 0.05), indicating that the number of residual support rods was negatively correlated with post-implantation days. The time for complete stent degradation was 124.8 days. The intimal area at 90 days after implantation was higher than that at 30, 60, 120 days after implantation (P < 0.05), while the lumen area was smaler than that at 30, 60, 120 days after implantation (P < 0.05). There was no significant difference in the intimal area and lumen area at latter three time points after implantation. To conclude, the degradation of the degradable AZ31 magnesium alloy stent in the rabbit abdominal aorta can be completed within 124.8 days, and at 90 days after the stent is implanted, vascular intimal hyperplasia and lumen stenosis are most serious, and then gradualy reduced.