Process of the degradation in vivo and biosafety of biodegradable magnesium alloy stent

Abstract

Objective: To observe the degradation process of biodegradable magnesium alloy stent (BMAS) in vivo in order to evaluate its degradation time and biological safety. Methods: Twenty-four male New Zealand white rabbits were divided into two groups: group A (n=12) and group B (n=12). The BMAS (a total of 12) was implanted in the infrarenal aorta of each rabbit in group A, while group B was the control group, without treatment. Color Doppler ultrasound was used at the 1, 2, 3, 4 months postoperatively to observe the degradation process of stents in group A. The arterial blood samples and main organs of two groups were also collected for biochemical examination and biosafety. Degradation assessment included transmission X-ray tomography (XRT), scanning electron microscope (SEM) and energy dispersion spectrum (EDS). Results: The XRT showed that the morphology of the stent was basically intact at 1 month after implantation, then scaffold composites were gradually degraded and absorbed. Degradation was basically completed at 4 months after operation. The early degradation products were Mg(2+) , then gradually replaced by Ca(2+) , P and other inorganic composition. There was no obvious adverse reactions in group A during the 4 months follow-up period. There was no statistical difference between the two groups in blood biochemical and pathological results (all P>0.05). Conclusion: BMAS can be degraded within 4 months in the abdominal aorta of rabbit, and the main degradation products are Ca(2+) and P, with good biosafety.