Basic techniques for long distance axon tracing in the spinal cord

Hellenbrand, Daniel J.; Kaeppler, Katie E.; Hwang, Euhaa; Ehlers, Mark; Toigo, Ross D.; Giesler, Joseph; Vassar-Olsen, Erika R.; Hanna, Amgad S.

doi:10.1002/jemt.22291

Cited by 11 publications

(9 citation statements)

References 46 publications

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“…Four weeks after SCI, seven rats from each group underwent anterograde axon tracing with a 10% biotinylated dextran amine (BDA) (Thermo Fisher Scientific Cat# D1956, RRID: AB_2307337) in saline, as previously reported [29]. Three of the seven rats received BDA injections in eight sites of the motor cortex (MC).…”

Section: Methodsmentioning

confidence: 99%

Sustained interleukin-10 delivery reduces inflammation and improves motor function after spinal cord injury

Hellenbrand

Reichl

Travis

et al. 2019

J Neuroinflammation

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Background The anti-inflammatory cytokine interleukin-10 (IL-10) has been explored previously as a treatment method for spinal cord injury (SCI) due to its ability to attenuate pro-inflammatory cytokines and reduce apoptosis. Primary limitations when using systemic injections of IL-10 are that it is rapidly cleared from the injury site and that it does not cross the blood–spinal cord barrier. Objective Here, mineral-coated microparticles (MCMs) were used to obtain a local sustained delivery of IL-10 directly into the injury site after SCI. Methods Female Sprague-Dawley rats were contused at T10 and treated with either an intraperitoneal injection of IL-10, an intramedullary injection of IL-10, or MCMs bound with IL-10 (MCMs+IL-10). After treatment, cytokine levels were measured in the spinal cord, functional testing and electrophysiology were performed, axon tracers were injected into the brainstem and motor cortex, macrophage levels were counted using flow cytometry and immunohistochemistry, and lesion size was measured. Results When treated with MCMs+IL-10, IL-10 was significantly elevated in the injury site and inflammatory cytokines were significantly suppressed, prompting significantly less cells expressing antigens characteristic of inflammatory macrophages and significantly more cells expressing antigens characteristic of earlier stage anti-inflammatory macrophages. Significantly more axons were preserved within the rubrospinal and reticulospinal tracts through the injury site when treated with MCMs+IL-10; however, there was no significant difference in corticospinal tract axons preserved, regardless of treatment group. The rats treated with MCMs+IL-10 were the only group with a significantly higher functional score compared to injured controls 28 days post-contusion. Conclusion These data demonstrate that MCMs can effectively deliver biologically active IL-10 for an extended period of time altering macrophage phenotype and aiding in functional recovery after SCI.

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Section: Methodsmentioning

confidence: 99%

Sustained interleukin-10 delivery reduces inflammation and improves motor function after spinal cord injury

Hellenbrand

Reichl

Travis

et al. 2019

J Neuroinflammation

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“…The latter is responsible for the specific binding to the GM1 membrane receptor, internalization, and retrograde transport [ 60 , 61 ]. Given these properties, cholera toxin-B subunit could be used either as a retrograde tracer [ 30 , 62 ] or as a targeted neurotoxin after conjugation with saporin [ 30 ]. A number of in vivo experiments have used cholera toxin-B saporin (CTB-Sap) and demonstrated its effectiveness in removing any neuron expressing GM1 ganglioside [ 30 , 49 , 63 – 65 ].…”

Section: Rodent Neurotoxic Spinal Cord Lesion Modelsmentioning

confidence: 99%

Neuroplasticity and Repair in Rodent Neurotoxic Models of Spinal Motoneuron Disease

Gulino

2016

Neural Plasticity

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Retrogradely transported toxins are widely used to set up protocols for selective lesioning of the nervous system. These methods could be collectively named “molecular neurosurgery” because they are able to destroy specific types of neurons by using targeted neurotoxins. Lectins such as ricin, volkensin, or modeccin and neuropeptide- or antibody-conjugated saporin represent the most effective toxins used for neuronal lesioning. Some of these specific neurotoxins could be used to induce selective depletion of spinal motoneurons. In this review, we extensively describe two rodent models of motoneuron degeneration induced by volkensin or cholera toxin-B saporin. In particular, we focus on the possible experimental use of these models to mimic neurodegenerative diseases, to dissect the molecular mechanisms of neuroplastic changes underlying the spontaneous functional recovery after motoneuron death, and finally to test different strategies of neural repair. The potential clinical applications of these approaches are also discussed.

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“…BDAs are highly sensitive tools for anterograde and retrograde pathway tracing studies of the nervous system (16,29). In the present study, microinjection of BDA was performed at multiple sites in the rat sensorimotor cortex to evaluate axonal sprouting following SCI, as impaired axon plasmic transport is followed by distal and partial proximal axon degeneration and fracture.…”

Section: Discussionmentioning

confidence: 99%

Resistance of interleukin-6 to the extracellular inhibitory environment promotes axonal regeneration and functional recovery following spinal cord injury

Tang

2017

International Journal of Molecular Medicine

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Interleukin-6 (IL)-6 was originally discovered as a factor that contributes to the secondary pathological and inflammatory response in the central nervous system (CNS) following injury. However, accumulating evidence suggests that IL-6 is also involved in functional and structural recovery following CNS injury by promoting axonal sprou-ting. This suggests a potential dual role of IL-6 in CNS injury. However, the definitive function of IL-6 in neural injury and the corresponding underlying mechanisms are still topics of controversy. The present study was carried out to examine the potential function of IL-6 in resistance to neurite growth‑inhibitory effects via regulation of the expression of growth associated protein-43 (GAP-43), myelin-associated neurite outgrowth inhibitor (Nogo-A) and its receptor (NgR). Rat dorsal root ganglion (DRG) neurons cultured in an inhibitory microenvironment mimicking injured CNS were used to investigate the effects of IL-6 on the outgrowth of neuronal processes. Additionally, IL-6 was subarachnoidally injected into rats to establish a spinal cord injury (SCI) model, and the neurobehavioral manifestations and neural morphology were subsequently evaluated to determine the effect of IL-6 on neural regeneration. Finally, the potential molecular mechanisms of IL-6-mediated rege-neration and functional recovery following CNS injury are discussed. The results of the present study demonstrated that the in vitro administration of IL-6 enhanced the neurite outgrowth of DRG neurons in a dose-dependent manner via resisting the inhibitory function of myelin proteins. All doses of the IL-6 subarachnoid injection improved the Basso, Beattie and Bresnahan scores following SCI, with a large number of axonal sproutings observed at the spinal lesion site, and several sprouting fibers being elongated and bypassing the lesion and entered the caudal spinal cord. Additionally, a significantly increased density area of diaminobenzidine-labeled neural fiber was observed in rats that received a subarachnoid injection of IL-6, and the rats exhibited increased expression of GAP-43 and decreased expression of Nogo-A. In conclusion, the results of the present study indicated that IL-6 interferes with the inhibitory functions of myelin proteins by upregulating the expression of GAP-43 and simultaneously downregulating the expression of Nogo-A and NgR to promote axonal sprouting and functional recovery following SCI.

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Basic techniques for long distance axon tracing in the spinal cord

Cited by 11 publications

References 46 publications

Sustained interleukin-10 delivery reduces inflammation and improves motor function after spinal cord injury

Sustained interleukin-10 delivery reduces inflammation and improves motor function after spinal cord injury

Neuroplasticity and Repair in Rodent Neurotoxic Models of Spinal Motoneuron Disease

Resistance of interleukin-6 to the extracellular inhibitory environment promotes axonal regeneration and functional recovery following spinal cord injury

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