反复冻融对同种异体人肌腱的生物力学影响

EFFECTS OF MULTIPLE FREEZE-THAW ON BIOMECHANICAL PROPERTIES OF HUMAN ALLOGRAFT TENDONS

目的分析反复冻融处理对同种异体人肌腱生物力学的影响,为同种异体移植物的处理与保存提供理论依据。方法从3具自愿捐赠新鲜尸体上取30根肌腱(指浅屈肌腱24根、拇长屈肌腱6根),随机分为6组,即新鲜组、冻融1次组、冻融2次组、冻融3次组、冻融5次组和冻融10次组,每组指浅屈肌腱4根,拇长屈肌腱1根。检测各组肌腱结构特性、力学性质及黏弹性变化等生物力学性质并进行比较。结果与新鲜组相比,拉断试验中冻融5次组及冻融10次组最大负荷、最大应力均明显减小,差异均有统计学意义(P<0.05),但最大拉伸及最大应变差异均无统计学意义(P>0.05)。应力松弛试验中,冻融5次组及冻融10次组应力松弛下降速度较快,与新鲜组相比差异均有统计学意义(P<0.05)。蠕变试验出现相似结果,冻融5次组及冻融10次组在100 N拉力作用下更早松弛,产生的蠕变较大,与新鲜组相比差异有统计学意义(P<0.05)。冻融1次、2次、3次组各指标与新鲜组比较差异均无统计学意义(P>0.05)。结论对同种异体移植物经深低温冻存后,冻存-复苏周期不宜超过3个,多周期反复冻融将削弱同种异体肌腱的生物力学性质,使其更容易疲劳、断裂。

Objective To explore the biomechanic effects of multiple freeze-thaw on human allograft tendons.Methods Thirty tendons（24 flexor digitorum superficialis tendons and 6 flexor pollicis longus tendons） were harvested from 3 fresh cadaver donors and were divided into 6 groups randomly（fresh group;1 cycle,2 cycle,3 cycle,5 cycle,and 10 cycle freeze-thaw groups）.There was 4 flexor digitorum superficialis tendons and 1 flexor pollicis longus tendon in each group.The structural and mechanical properties as well as viscoelastic change were estimated.Results The results of the structural and mechanical properties in 1 cycle,2 cycle,and 3 cycle freeze-thaw groups were similar to that of the fresh group（P 〉 0.05）.The tendons in 5 cycle and 10 cycle freeze-thaw groups showed a significantly lower ultimate load and maximum stress when compared with those of fresh group（P 〈 0.05）,but there was no significant difference in maximum tensile or maximum strain（P 〉 0.05）.Moreover,the tendons in 5 cycle and 10 cycle freeze-thaw groups had a significant increase in viscoelastic properties when compared with fresh group（P 〈 0.05）.Conclusion In the cryopreservation of tendon allografts,the cycle of freeze-thaw should not exceed 3 times.Multiple cycle freeze-thaw will weaken the biomechanical properties of tendon allografts,which make grafts easier to fatigue or even rupture.