High-concentration glutaraldehyde fixation of bovine pericardium in organic solvent and post-fixation glycine treatment: in vitro material assessment and in vivo anticalcification effect☆

Abstract

Glutaraldehdye (GA)-fixed xenografts are widely used in cardiovascular surgery. The objective of this study was to evaluate the anticalcification effect of glycine treatment and high-concentration GA fixation in organic solvent on GA-fixed bovine pericardium, and to evaluate the possible synergistic effect of combined treatment. Bovine pericardial tissues were divided into four groups according to the methods of treatment. Group 1 consisted of tissues fixed with 0.5% GA (control), group 2 fixed with 0.5% GA and post-treated with glycine, group 3 fixed with 2% GA in organic solvent (65% ethanol+5% octanol), and group 4 fixed with 2% GA in organic solvent and post-treated with glycine. The material characteristics of the treated tissues were assessed by amino acid analysis, thermal stability test, uniaxial mechanical test and light microscopy. The tissues were subcutaneously implanted into 4-week-old rats for 8 weeks, and the calcium contents of the explanted tissues were measured. Differently treated tissues resulted in no significant alterations in material characteristics and morphology as assessed by amino acid analysis, thermal stability test, uniaxial mechanical test, and light microscopy. Median calcium contents of groups 1, 2, 3, and 4 were 80.5 μg mg(-1), 1.0 μg mg(-1), 0.5 μg mg(-1) and 1.7 μg mg(-1), respectively. The calcium contents of groups 2, 3 and 4 were all significantly lower than that of group 1 (p < 0.05). Post-fixation treatment with glycine, high-concentration GA fixation in organic solvent and combined treatment of these all strongly prevented calcification of GA-fixed bovine pericardium in rat subcutaneous implantation model.