The design, development, and in vivo performance of intestinal anastomosis ring fabricated by magnesium‑zinc‑strontium alloy.

In the current work, an intestinal anastomosis ring made of magnesium‑zinc‑strontium (Mg-Zn-Sr) alloy was developed and fabricated in order to take advantages of the appropriate biocompatibility and degradability of Mg-based alloys. As-fabricated anastomosis rings were implanted into the intestinal tracts of Bama miniature pigs to evaluate their biological performance in vivo. At the injury site, the formation of edema and granulation tissue was observed for 2 weeks after surgery. Till week 4, the edema transformed to firm scar tissue, which reached the healing standard of intestinal tissue. The levels of biochemical indicators such as blood routine, liver and kidney functions as well as electrolytes were all under normal conditions, indicating that the implantation of Mg alloy did not have remarkable influence on the blood system as well as liver and kidney functions. Pathological results revealed that no obvious abnormality was found in heart, liver, spleen, lung, kidney and brain tissues. The Mg ions were found to be excreted from the body through urine. The intestinal anastomosis ring could be discharged through excretion around 2 weeks after surgery, of which the surface was corroded and covered by a layer of Ca- and P-containing minerals. According to histological images, a mild inflammatory response was noticed on week 2. At this stage, dilated and congested capillaries were found in the muscular layer. Moreover, the mucosal layer and villi at the injury site were disordered. Till week 4, the muscular and mucosal layer were similar to their healthy counterparts even though the villi were slightly shorter than normal ones. Together, the results indicate that Mg-Zn-Sr alloy is a promising candidate for the fabrication of biodegradable intestinal anastomosis ring.