Hemostasis in vivo

The hemostatic ability of the MACS-2 was evaluated by lethally normal/heparinized rat liver perforation wound models, normal pig liver perforation wound model, and pig femoral artery bleeding model. Gauze, GS, CELOX™, CELOX™-G, ACS, and MCS-2 were used as controls. All animal experiments were performed with the approval of the Animal Experimental Ethics Committee of Nankai University (Protocol number: 2021-SYDWLL-000423).

Normal and heparinized rat liver perforation wound models: A rat (male, weight of 250–300 g, 7–8 weeks) was anesthetized by injecting 10 wt% chloral hydrate in a dose of 1 mL/300 g. Then, the rat’s abdomen was incised, and the liver was lifted and placed onto the surface of the preweighted filter paper. Next, a circular perforation wound (diameter of 6 mm) was created on the liver to induce hemorrhaging. Finally, the cylindrical MACS-2 (diameter of 8 mm) was compressed to squeeze out water and filled into the wound cavity. The hemostatic process was recorded with a digital camera. The blood loss was measured by determining the total weight of the blood absorbed by the filter paper and hemostats. The hemostatic time was recorded with a timer. The heparin solution (50UI) was injected into the rat (male, weight of 250–300 g, 7–8 weeks) through a vein at a dose of 2 mL/kg and used for the construction of the heparinized rat liver perforation wound model. Other procedures were similar to the method mentioned above.

Lethal pig liver perforation wound model: Bama miniature pig (male, weight of 15 kg, 3 months) was anesthetized by injecting a mixed solution of midazolam and xylazine hydrochloride (2/1, v/v) into its muscle at a dose of 0.14 mL/1 kg. Then, the abdomen of the pig was incised, and its liver was taken out and placed onto the surface of the filter paper. Next, a 15 mm-diameter circular perforation wound was made on the liver. After bleeding, the cylindrical MACS-2 (diameter of 18 mm) was compressed to squeeze out the free water and filled into the wound cavity. The hemostatic process was recorded with a digital camera. The total blood loss from each liver was weighed and the hemostatic time was recorded.

Lethal pig femoral artery bleeding model: Bama miniature pig (male, weight of 15 kg, 3 months) was anesthetized and fixed. Then, the pig’s femoral artery was injured to induce bleeding. Next, the shape-fixed MACS-2 was injected into the wound cavity to stop bleeding. The hemostatic process was recorded with a digital camera.