Session: 12-07-04: Mechanics of Soft Materials
Paper Number: 99928
99928 - Constitutive Properties for Myelin Sheath
One of the fundamental aspects of neuronal communication is associated with the glial cells and the link between the glial and the neuronal cell. Following any injury incident, this communication between the cells is susceptible to damage and ultimately resulting in the collapse of neuronal communication. Glial cells are one of the fundamental components of the white matter of brain tissue and among them the most important glial cells are the Oligodendrocytes, since they are directly tethered to the axons. Oligodendrocytes contribute to faster signal transmission along the axons by reducing the capacitance along the axonal membrane. These cells connect to the axons by extending themselves and producing a fatty layer of substance around the axons. This layer of fat around the axons is called the myelin sheath. With the aid of this layer, oligodendrocytes promote the speed of electrical signal transmission. Following any injury, the oligodendrocytes are more prone to damage and the impaired connection between the oligodendrocyte and neuron hampers neurotransmission leading to cell death and neurodegenerative disorder. It has been found that, under traumatic force the myelin sheath may undergo lysis hampering signal transmission along neurons. In our study, a damage criterion of the myelin sheath following injury has been focused on. The primary objective of our research work lies in evaluating a threshold value for hampering the neuronal communication from mechanical point of view. We believe that it is imperative to address the impact of myelin sheath as it is profoundly associated with the saltatory conduction through the axon. Using CHARMM-GUI and applying periodic boundary conditions, a representative volume element of Myelin sheath is developed. In our study a method has been developed where non-equilibrium molecular dynamics simulation (NEMD) can be implemented to find material properties for complex biological systems. Myelin sheath are stacks of lipid bilayer interconnected by membrane protein. These proteins in the myelin sheath contributes to load bearing capacity and rigidity of the entire Myelin structure. Using non-equilibrium molecular dynamics simulation and reasonable assumptions, the bulk modulus has been evaluated for the representative volume element. Theoretical studies discovered that an unmyelinated axon can withstand the strain up to a certain threshold before rupture with the failure strain and stress varying between 6-11% and 5-19.8 MPa respectively. Presumably, with the models, we find that the value of failure strain and stress is higher for the myelinated axon. In addition to that, we aim at evaluating the conditions at the interface of the protein and the lipid membranes that would provide a threshold for compactness of the myelin prior to lysis following trauma. In summary, using our computational models, we can forecast how brain cells will respond to varying amplitudes of mechanical stress during cellular-level trauma.
Presenting Author: Fairuz Maliha University of Texas at Arlington
Presenting Author Biography: Ms. Fairuz Maliha is a graduate in the Mechanical and Aerospace Engineering Department at the University of Texas at Arlington. Her research is related to traumatic brain injury mechanisms, molecular dynamics and image analysis.
Authors:
Fairuz Maliha University of Texas at ArlingtonAshfaq Adnan University of Texas at Arlington
Constitutive Properties for Myelin Sheath
Paper Type
Technical Presentation