Mechanical differences between mammalian pericardia are due to differences in type III collagen content and crosslinking

This study demonstrates significant differences in mechanical function between the pericardial tissue of dogs, pigs, sheep, and calves and shows that these differences correlate strongly with differences in Type III collagen content and crosslinking. Cyclic loading and forced vibration results both showed that the thinner canine and porcine pericardial tissues were significantly stiffer and less extensible than the thicker ovine and bovine tissues (see Figure 1 for results at 1 Hz). However, forced vibration and stress relaxation experiments showed that these differednces were confined to the elastic component of their behaviour; the degree of viscoelasticity was similar among the tissues, mean phase angles at 1 Hz averaging 4.40 ± 0.36°.