[Structural change analysis of pig aorta before and after freeze-drying]

Pig aortic vessels were processed by vacuum freeze-drying and then the aotic vessels were scanned and compared by CT, microscopic and texture analyzer. These processes presented a new method for preserving the vessels. Morphological changes of the vessels were tracked by Micro-CT, and mechanical properties were compared by texture analyzer combining with microscopic observation for structures and tissues. Results showed that the wall of the vessels became thinner by freeze-drying. After rehydration, the membrane structure was generally maintained, and the elastic fibers were more orderly arranged so that they were close to fresh vessels. In the area of mechanical property, the maximum puncture stress and axial tensile stress of rehydrated blood vessels were stronger than that of the fresh, while circumferential tensile stress was weaker than that of the fresh. Finally, analysis also showed that the freeze-dried vessel was basically remained the original morphological structure. The pores in vessel fiber and stratification during drying may be beneficial to the host cell invasion and angiogenesis, so it is expected to be a new effective means to save the blood vessels. Currently, four pigs have been transplanted with the rehydrated vessels, and all of the four have survived for more than 3 weeks.