Improved tendon radioprotection by combined cross-linking and free radical scavenging.
Allograft safety is a great concern owing to the risk of disease transmission from nonsterile tissues. Radiation sterilization is not used routinely because of deleterious effects on the mechanical integrity and stability of allograft collagen. We previously reported several individual cross-linking or free radical scavenging treatments provided some radioprotective effects for tendons. We therefore asked whether a combination of treatments would provide an improved protective effect after radiation exposure regarding mechanical properties and enzyme resistance. To address this question we treated 90 rabbit Achilles tendons with a combination of cross-linking (1-ethyl-3-[3-dimethyl aminopropyl] carbodiimide [EDC]) and one of three scavenging regimens (mannitol, ascorbate, or riboflavin). Tendons then were exposed to one of three radiation conditions (gamma or electron beam irradiation at 50 kGy or unsterilized). Combination-treated tendons (10 per group) had increases in mechanical properties and higher resistance to collagenase digestion compared with EDC-only and untreated tendons. Irradiated tendons treated with EDC-mannitol, -ascorbate, and -riboflavin combinations had comparable strength to native tendon and had averages of 26%, 39%, and 37% greater, respectively, than those treated with EDC-only. Optimization of a cross-linking protocol and free radical scavenging cocktail is ongoing with the goal of ensuring sterile allografts through irradiation while maintaining their structure and mechanical properties.
Seto
Aaron
A
Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, UMDNJ-Robert Wood Johnson Medical School, 51 French Street, Orthopaedic Surgery Room 424, PO Box 19, New Brunswick, NJ, 08903, USA.
Gatt
Charles J
CJ
Dunn
Michael G
MG
D000125:Achilles Tendon / Q000187:drug effects* / Q000528:radiation effects*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D001696:Biomechanical Phenomena; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004195:Disease Models, Animal; D016166:Free Radical Scavengers / Q000494:pharmacology*; D008353:Mannitol / Q000494:pharmacology; D008422:Materials Testing; D011817:Rabbits; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control; D011897:Random Allocation; D012016:Reference Values; D012256:Riboflavin / Q000494:pharmacology; D012680:Sensitivity and Specificity; D013709:Tendon Transfer / Q000009:adverse effects / Q000379:methods; D013718:Tensile Strength; D020858:Tissue and Organ Harvesting / Q000379:methods; D014184:Transplantation, Homologous
D003432:Cross-Linking Reagents; D016166:Free Radical Scavengers; D008353:Mannitol; D001205:Ascorbic Acid; D012256:Riboflavin