Biomechanical comparison of xenogeneic bone material treated with different methods.

Abstract

Bone xenografting is considered one of the most effective ways to address the shortage of bone autografts and allografts. Various methods have been employed to minimize the immune rejection issues associated with bone xenografts. However, the side effects of such methods on bone biomechanical properties remain unclear. As such, the objective of this study was to compare the influence of different treatments on the biomechanical properties of porcine bones. Fresh pig ribs were cut into 1.5 × 0.5 × 0.4 cm specimens, which were randomly divided into four groups and subjected to different modification regimes: group A by degreasing and partial deproteinization, group B by cryopreservation, group C by cryopreservation and enzyme digestion, and group D was a control group using fresh bone. Biomechanical tests and α-Gal antigen detection were performed for all groups. In the axial compression test, the values for maximum load were as follows: group D > group C > group B > group A. The maximum load in group A was significantly less than in the other groups (P < .05). There were no differences between groups D, C, and B in terms of the maximum stress and elastic modulus (P > .05). The maximum stress and elastic modulus values recorded for group A were significantly less than for the other groups (P < .05). There were no significant differences in the maximum load or elastic modulus among groups B, C, and D, in the three-point bending test (P > .05). However, the maximum load and elastic modulus values recorded for group A were significantly lower than the other groups (P < .05). In groups A and C, no α-Gal antigen-positive expression was detected. In group B, there was low level α-Gal antigen-positive expression, while a high level of α-Gal antigen-positive expression was observed in fresh bone samples. The results indicated that xenogeneic bone subjected to degreasing and partial deproteinization had the worst biomechanical properties. Cryopreservation and cryopreservation with enzyme digestion had little effect on the bone biomechanical properties, although enzyme digestion resulted in the complete elimination of the α-Gal antigen. Cryopreservation with enzyme digestion treatment presented the best results in terms of removing the immune-response triggering α-Gal antigen, while preserving the good biomechanical properties of bone xenografts.