Temperature-based protection of biochemical and biomechanical characteristics during 25 kGy 60Co irradiation for allograft tendons

Abstract

Abstract Background: Nowadays, there is a lack of effective treatment for reducing damage to the collagen proteins in tendons during the gamma irradiation process. We aim to investigate different temperatures on the protection of allogeneic tendons during 25kGy 60Co gamma irradiation. Methods: Based on different temperatures during irradiation, twenty-four allogeneic tendons were divided into groups of -70 °C, 0 °C, and room temperature (RT). The arrangement and spatial structure of collagen fibers were observed by HE and Masson staining, polarizing microscope after Sirius Red staining was used to observe collagen curl periods, damaged collagen protein was assessed using free hydroxyproline tests. Tensile fracture and cyclic loading tests were performed, then calculated the elastic modulus, maximum stress, maximum strain, strain energy density, and cyclic creep strain. Results: In the -70 °C group, the structure and morphology of collagen fibers were significantly better than in the 0 °C group. At -70 ºC the damaged collagen was the lowest, with 46.27 and 50.03% improvement compared to that at 0ºC (P = 0.016) and RT (P < 0.004). The maximum stress of -70 °C (68.19 ± 30.11 MPa) is superior to that at 0 °C (36.58 ± 12.00 MPa) and RT (41.27 ± 16.34 MPa). Conclusions: Cryogenic temperature has a protective effect on allograft tendons at 25kGy gamma radiation, and -70 °C provides better protection than 0 °C