Development of a Mechanical Testing Assay for Fibrotic Murine Liver

Abstract

Hepatic fibrosis is a progressive disease in which progression is correlated to liver mechanical properties. This correlation may be used to assess the state of the disease, and hence methods to determine the elastic modulus of the liver are of considerable interest. In order to assess the diseased state of the liver accurately, controlled experiments to establish baseline modulus values for healthy livers as well as diseased livers must be conducted. The focus of this work is the development of a protocol for mechanical testing combined with finite element modeling to allow for the evaluation of normal and fibrotic murine livers using multiple testing methods. The developed system employs a portion of liver tissue suspended in a cylindrical gel for CT imaging and mechanical testing. A finite element model is built from the CT images, and boundary conditions are imposed in order to simulate the testing conditions of the gels. The resulting model surface stress is compared to that obtained during mechanical testing which subsequently allows for direct evaluation of the liver modulus. Though the sample sizes for this initial work were small, the preliminary results indicate that the livers can be identified within the gel, and the fibrotic livers can be identified as having a higher modulus than the control livers, thus implying that the developed gel-tissue assay system could be used for controlled evaluation of soft-tissue moduli.