Laser Microbeam Targeting of Single Nerve Axons in Cell Culture

Hyun, Nicholas; Shi, Linda Z.; Berns, Michael W.

doi:10.1007/978-1-4939-2152-2_16

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…The microscopic dose dependence of dendritic snipping and neuron death pathways are mechanistic models used to hypothesize that energy deposition in dendrites initiates the snipping processes at the same spatial location, while the probability of occurrences can be represented by simple probabilistic models. Targeted pruning (70, 71) rather than random dose deposition to dendrites can help us understand neuron-specific DL reductions under dendrite injuries. Molecular programs for dendrite degeneration may be independent of the age-related pruning of neurons as well as caspase-dependent apoptosis (21).…”

Section: Discussionmentioning

confidence: 99%

Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons

Alp

Cucinotta

2018

Radiation Research

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Exposure to heavy-ion radiation during cancer treatment or space travel may cause cognitive detriments that have been associated with changes in neuron morphology and plasticity. Observations in mice of reduced neuronal dendritic complexity have revealed a dependence on radiation quality and absorbed dose, suggesting that microscopic energy deposition plays an important role. In this work we used morphological data for mouse dentate granular cell layer (GCL) neurons and a stochastic model of particle track structure and microscopic energy deposition (ED) to develop a predictive model of high-charge and energy (HZE) particle-induced morphological changes to the complex structures of dendritic arbors. We represented dendrites as cylindrical segments of varying diameter with unit aspect ratios, and developed a fast sampling method to consider the stochastic distribution of ED by δ rays (secondary electrons) around the path of heavy ions, to reduce computational times. We introduce probabilistic models with a small number of parameters to describe the induction of precursor lesions that precede dendritic snipping, denoted as snip sites. Predictions for oxygen (O, 600 MeV/n) and titanium (Ti, 600 MeV/n) particles with LET of 16.3 and 129 keV/μm, respectively, are considered. Morphometric parameters to quantify changes in neuron morphology are described, including reduction in total dendritic length, number of branch points and branch numbers. Sholl analysis is applied for single neurons to elucidate dose-dependent reductions in dendritic complexity. We predict important differences in measurements from imaging of tissues from brain slices with single neuron cell observations due to the role of neuron death through both soma apoptosis and excessive dendritic length reduction. To further elucidate the role of track structure, random segment excision (snips) models are introduced and a sensitivity study of the effects of the modes of neuron death in predictions of morphometric parameters is described. An important conclusion of this study is that δ rays play a major role in neuron morphological changes due to the large spatial distribution of damage sites, which results in a reduced dependence on LET, including modest difference between O andTi, compared to damages resulting from ED in localized damage sites.

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Section: Discussionmentioning

confidence: 99%

Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons

Alp

Cucinotta

2018

Radiation Research

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“…Among them are the use of femtosecond near-infrared 5 and nano-to picosecond pulsed lasers. [6][7][8][9] In a recent in vitro model, Kim et al combined a laser microdissection (LMD) setup with microfluidics to perform more localized and reproducible axotomy. 10 Microfluidic platforms are suitable in vitro tools to separate axonal physiology and pathology from that of their cell bodies.…”

Section: Introductionmentioning

confidence: 99%

A microchannel device tailored to laser axotomy and long-term microelectrode array electrophysiology of functional regeneration

et al. 2015

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We designed a miniaturized and thin polydimethylsiloxane (PDMS) microchannel device compatible with commercial microelectrode array (MEA) chips. It was optimized for selective axonal ablation by laser microdissection (LMD) to investigate the electrophysiological and morphological responses to a focal injury in distinct network compartments over 45 days in vitro (45 DIV). Low-density cortical or hippocampal networks (<3500 neurons per device) were cultured in quasi-closed somal chambers. Their axons were selectively filtered through neurite cavities and guided into the PDMS microchannels aligned over the recording electrodes. The device geometries amplified extracellularly recorded signals in the somal reservoir and the axonal microchannels to detectable levels. Locally extended areas along the microchannel, so-called working stations, forced axonal bundles to branch out and thereby allowed for their repeatable and controllable local, partial or complete dissections. Proximal and distal changes in the activity and morphology of the dissected axons were monitored and compared to those of their parent networks and of intact axons in the control microchannels. Microscopy images confirmed progressive anterograde degeneration of distal axonal segments over four weeks after surgery. Dissection on cortical and hippocampal axons revealed different cell type- and age-dependent network responses. At 17 DIV, network activity increased in both the somal and proximal microchannel compartments of the dissected hippocampal or cortical axons. At later days (24 DIV), the hippocampal networks were more susceptible to axonal injury. While their activity decreased, that in the cortical cultures actually increased. Subsequent partial dissections of the same axonal bundles led to a stepwise activity reduction in the distal hippocampal or cortical axonal fragments. We anticipate that the MEA-PDMS microchannel device for the combined morphological and electrophysiological study of axonal de- and regeneration can be easily merged with other experimental paradigms like molecular or pharmacological screening studies.

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Laser Microbeam Targeting of Single Nerve Axons in Cell Culture

Cited by 2 publications

References 10 publications

Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons

Biophysics Model of Heavy-Ion Degradation of Neuron Morphology in Mouse Hippocampal Granular Cell Layer Neurons

A microchannel device tailored to laser axotomy and long-term microelectrode array electrophysiology of functional regeneration

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