Session: 06-01-02: Injury and Damage Biomechanics II - Organ and Tissue Injury Biomechanics 2

Paper Number: 150608

150608 - Viscoelastic Response of the Myelin Sheath: A Molecular Dynamics Simulation Study 

Neuronal cells, specifically axons, are encapsulated with a repetitive layer of fat termed as the myelin sheath. Myelin sheath contributes to insulating the nerve cells and establishing an uninterrupted signal transmission and communication with the rest parts of the brain. Impaired neurotransmission is probable disarray at the cellular and subcellular level following trauma. Previous studies have been primarily focused on the response of an unmyelinated axon and the failure stress and strain have been concluded in the range of 6-11% and 5-19.8 MPa respectively. The mechanical response of the myelin sheath is of significance as it accelerates neurotransmission by improving reaction times. Earlier studies have hypothesized that myelin originates from two different types of cells, Schwann cells in the peripheral nervous system (PNS) and Oligodendrocytes in the central nervous system (CNS) respectively. Post injury, signal transmission is hampered at the cellular and subcellular due to the possibility of degenerating insulation around the axon. Damage to the myelin sheath from a mechanical standpoint is an important concern. The major objective of our study is to obtain constitutive relations and failure properties of myelin sheath. Through our research, we aim to correlate the response of the myelin sheath in terms of such relations that highlight the parameters to give an understanding of the mechanical response of the myelin sheath. Membrane proteins commonly known as MBP (Myelin Basic Protein) are responsible for interconnecting bilayers in spiral pattern over the axon to form the myelin sheath. In our previous studies, we studied the behavior of myelin sheath at the subcellular level and obtained a maximum allowable tensile strain of 10 percent. Following this study, we have also studied the mechanics of multilayer myelin sheath under high strain rate scenarios. Our multilayer myelin model is formed with two lipid bilayers interconnected by a membrane protein. Since the membrane protein holds the lipid bilayers together so it is a contributing element of the overall stability of the myelin sheath. Under high strain rates, we have assessed the damage criteria of myelin sheath degeneration by quantifying the strain under which the bilayers are detached from the membrane protein. In conclusion, it can be stated that the overall response of the myelin sheath is mostly dependent on the interfacial properties. With our proposed study we aim to highlight this interfacial response in terms of constitutive relations that would help in understanding the viscoelastic response of the myelin sheath under varying magnitudes of mechanical trauma.

Presenting Author: Fairuz Maliha University of Texas at Arlington

Presenting Author Biography: I have been working as a Graduate Research Assistant at Multiscale Mechanics and Physics lab. I specialize in developing molecular models and studying behavior of cellular components of the brain through molecular dynamics simulations.

Authors:

Fairuz Maliha University of Texas at Arlington
Ashfaq Adnan University of Texas at Arlington