Uniaxial stretch-induced axonal injury thresholds for axonal dysfunction and disruption and strain rate effects on thresholds for mouse neuronal stem cells

Abstract

In this paper, the proposed study aims to achieve a better understanding of neuronal tolerance and contribute to the prediction of the secondary degeneration of diffuse axonal injury (DAI). Therefore, a uniaxial stretching device which subjected cultured neurons to uniaxial stretch was employed to evaluate the effect of strain and strain rate along axon to realize the injury threshold. Neurons differentiated from mouse neuronal stem cells were injured and the morphology was observed before and after stretching with strains of 0.10, 0.12, 0.18, 0.23 at strain rates of 8, 11, 19, 26 s^-1 respectively. Results suggest that the threshold for axonal dysfunction is around 0.18 strain whereas the threshold for axonal disruption is around 0.23 and the results of strain rate effect investigations on axonal dysfunction and disruption around these threshold values indicated that higher strain rate values such as 50 s^-1 may have diminishing effects on threshold for axonal disruption.