Biomechanical properties of glutaraldehyde treated human pericardium

Autologous pericardium, for repair of congenital heart defects, can be used in its fresh non-treated state, or after chemical fixation with glutaraldehyde solution as a biomaterial for surgical repair of congenital heart anomalies. The aim of this experimental study is to investigate changes of biomechanical properties and resistance to proteolytic degradation of human pericardium, after harvesting with glutaraldehyde solution. After taken out of a pericardium from anterior part of pericardial sac at the time of operation it was fixed with 0.2% solution of glutaraldehyde for 6 minutes. Some glutaraldehyde treated and untreated samples were incubated in collagenase solution (100 Uml^-1) for 2 hours at 37°C and proteolytic effect was estimated with gravimetric method. For investigation of biomechanical properties uniaxial tensile tests were performed with testing machine Zwick-Roell Z010. There were set up 18 pieces of fresh human pericardium and 11 pieces of glutaraldehyde-treated human pericardium. There is difference (p<0.05) of ultimate strain (ε_max) between fresh pericardium ε_max=0. 119±0.037 and glutaraldehyde treated human pericardium ε_max= 0.098±0.015, respectively. There is difference (p<0.05) of ultimate stress (σ_max) between non-treated pericardium σ_max=3.14±0.70 MPa and glutaraldehyde treated human pericardium σ_max=6.20±1.47 MPa. There is difference (p<0.05) of tangential modulus of elasticity (E) between non-treated and glutaraldehyde treated human pericardium: 98.67±20.75 MPa and 50.25±16.04 MPa, respectively. Gravimetric data demonstrated that glutaraldehyde treatment resulted in statistically significant improvement in resistance of human pericardium to proteolytic degradation. Material became stiffer and stronger after treatment with glutaraldehyde solution as well as more resistant to proteolytic degradation then non-treated one. These biomechanical differences could be explained by formation of collagen crosslink after glutaraldehyde treatment. We conclude that treating with glutaraldehyde improve the application of autologous human pericardium as the plastic material for surgical repair of congenital heart anomalies by improving its biomechanical properties and increasing resistance to proteolytic degradation.