Effects of solvent preservation with or without gamma irradiation on the material properties of canine tendon allografts

Abstract

We studied the effects of solvent preservation with and without gamma irradiation on the material properties and morphology of canine tendons. Twenty-four paired tendons were harvested from both hind limbs of eight dogs. The tendons from the right legs were divided into three treatment groups of eight tendons each. In the first group, the tendons were subjected to solvent preservation for sterilization and drying (solvent group). In the second group, the tendons were treated in the same manner and then were sterilized by gamma irradiation (solvent/gamma group). The same treatments were applied to the tendons in the third group but in reverse order (gamma/solvent group). Tendons from the contralateral left legs were frozen immediately for use as controls for each corresponding treatment group. Histologically, the tendons treated with solvent, with or without gamma irradiation, had a more prominent wavy pattern in the collagen fibers than the control tendons. Mechanically, the tangent moduli for the solvent, solvent/gamma, and gamma/solvent groups were 58, 53, and 99%, respectively, of each contralateral control. The respective tensile strengths were 85, 39, and 86% of that of the contralateral control. The tendons in the solvent/gamma group underwent the most severe changes in material properties; the tendons in the gamma/solvent group changed the least. This suggests that gamma irradiation followed by solvent drying is the procedure of choice for the preservation of tendon allografts.

Effect of freeze-drying and gamma irradiation on biomechanical properties of bovine pericardium

“…Hence, the weakening effects of gamma rays on biomechanical properties of freeze-died bovine pericardium observed in this study could be due to damaging effect of gamma rays on collagen bundles molecules that was reported by Maeda et al (1993) at doses commonly used for sterilization of biomedical products. The thickness measured in this study for both the freeze-dried and the irradiated freeze-dried bovine pericardium was within the range reported by Tokuhiro et al (1995) for the thickness of normal bovine parietal pericardium.…”

Improved Tendon Radioprotection by Combined Cross-linking and Free Radical Scavenging

“…Sterilization is accomplished predominantly with ionizing radiation, specifically gamma and electron beam (ebeam) radiation derived from gamma rays and high-energy electrons, respectively. Unfortunately, these sources of energy cause damage to collagenous structures [4,10,17,22,28,36]. The primary cause of damage is modification of collagen molecules by free radicals generated from irradiation of water and oxygen [4,37].…”

Good preservation of initial mechanical properties in lipid-extracted, disinfected, freeze-dried sheep patellar tendon grafts

“…Some banks use freeze-drying in combination with a preliminary rinse in ethanol or solvent agents. This approach also provides good initial mechanical properties, decontamination and preservation of osteoinductive properties (Delloye et al 1991, Maeda et al 1993, Zimmerman et al 1994). …”

“…Further processing of bone allografts by freeze-drying or lipid extraction reduces the immune response (Friedlaender et al 1984, Thorén et al 1995. Previous studies on the processing of soft tissue transplants have been carried out in different conditions-e.g., freezing or freeze-drying (Thomas and Gresham 1963, Turner et al 1988, Bechthold et al 1994, Silver et al 2000, disinfection with solvent agents (Maeda et al 1993, Zimmerman et al 1994, Burd et al 2000 or sterilization (Bechthold et al 1994, Jackson et al 1990, Johnson et al 1999. None of these methods meets all the requirements for a strong, safe and minimally-immunogenic transplant and they are therefore not recommended by the European Association of Tissue Banks (EATB 1997).…”