Tensile Testing of Single Collagen Fibrils from Achilles Tendons from an Osteogensis Imperfecta Mouse Model

Abstract

The homozygous oim mouse model of osteogenesis imperfecta forms homotrimeric collagen type I molecules, which assemble into fragile bone tissue. Counterintuitively, it has been shown that individual collagen fibrils from oim/oim (severe OI type III) tail tendons have higher ultimate stress compared to wild-type (WT) fibrils. However, collagen fibril mechanics are in part steered by the prevalence of enzymatic and non-enzymatic crosslinks between collagen molecules, and elevated non-enzymatic crosslinks have been reported in the bones of the oim mouse, compared to WT. So far, only fibrils from the positional tail tendons were investigated from oim/oim and littermate WT mice. No data exists on fibrils from energy-storing tendons. To fill this gap, here we report the mechanical properties of oim/oim and WT fibrils obtained from Achilles tendons.