2025, Vol. 29 ›› Issue (28): 6046-6051

Changes in properties of treated allogeneic tendons after multiple freeze-thaw cycles

Hu Kai1, Guo Yongqin1, Shao Yiran1, Wang Jingjing2   

Abstract: BACKGROUND: Allogeneic tendons are often used in clinical treatment of tendon and ligament injuries, which need to be treated before clinical application. At present, allogeneic tendons will face multiple freeze-thaw cycles after cryopreservation, but there is no relevant research on the changes in the properties of the treated allogeneic tendon after several freeze-thaw cycles.
OBJECTIVE: To explore the changes in mechanical properties and composition of allogeneic tendon after multiple freeze-thaw cycles.
METHODS: The treated allogeneic tendon was frozen and thawed 3, 6, and 10 times at -40 ℃ (or -80 ℃), respectively. The mechanical test, DNA content, glycosaminoglycan sulfate, hydroxyproline content and total protein content of the allogeneic tendon after freezing and thawing were detected.
RESULTS AND CONCLUSION: (1) There was no significant difference in the maximum load, maximum load elongation, tensile strength and elastic modulus between groups after freezing-thawing cycles for 3, 6, and 10 times at -40 ℃ (P > 0.05). There was no significant difference in the maximum load and maximum load elongation between the groups after freezing-thawing cycles for 3, 6, and 10 times at -80 ℃ (P > 0.05). The tensile strength of the group with 3 cycles of freezing and thawing was higher than that of the groups with 6 and 10 cycles of freezing and thawing (P < 0.05). The elastic modulus of the group with 3 cycles of freezing and thawing was higher than that of the group with 10 cycles of freezing and thawing (P < 0.05). (2) The freezing and thawing times did not affect the contents of DNA, hydroxyproline, total protein, and sulfated glycosaminoglycan in allogeneic tendon when stored at -40 ℃ (or -80 ℃). (3) These findings suggest that in -40℃ storage, the performance of the allogeneic tendon should not be affected by taking out and putting back the tendon less than 10 times, while in -80 ℃ storage, the allogeneic tendon should be taken out and put back less than 6 times.

Key words: allogeneic tendon, freeze-thaw cycle, mechanical property, component detection, process treatment, engineered tendon