Cryopreserved Porcine Tendons Preserve Cell Viability After Thawing

Controlled cryopreservation is an important method for storage of tissue grafts in skin banking, reproductive medicine and other domains. Although the availability of cryopreserved flexor tendons would be highly beneficial in reconstructive surgery, especially in complex reconstructions for which grafting material is limited, only a few studies have dealt with transplanted tendons. We achieved successful cryopreservation of porcine flexor tendons in 2 cryoprotective media: dimethyl sulfoxide and glycerol. Their viability was shown using a quantitative colorimetric MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazolium bromide) assay. For comparison of native and cryopreserved tendons (n = 7 samples each), the adopted viability index was the ratio of MTT-dependent optical density and tendon weight. The viability index of native samples did not change significantly after cryopreservation and thawing. The proliferative capacity of tendon fibroblasts after thawing was shown in primary cell cultures. The described cryopreservation protocol and MTT assay may provide a basis for future autografting of human tendons.