Source Paper
BDNF and NT-4/5 Prevent Atrophy of Rat Rubrospinal Neurons after Cervical Axotomy, Stimulate GAP-43 and Tα1-Tubulin mRNA Expression, and Promote Axonal Regeneration
Nao R. Kobayashi, Da-Peng Fan, Klaus M. Giehl, Annie M. Bedard, et al.
Source Paper
Nao R. Kobayashi, Da-Peng Fan, Klaus M. Giehl, Annie M. Bedard, et al.
Journal of Neuroscience • 1997
Rubrospinal neurons (RSNs) undergo a marked atrophy in the second week after cervical axotomy. This delayed atrophy is accompanied by a decline in the expression of regeneration-associated genes such as GAP-43 and Tα1-tubulin, which are initially elevated after injury. These responses may reflect a deficiency in the trophic support of axotomized RSNs. To test this hypothesis, we first analyzed the expression of mRNAs encoding the trk family of neurotrophin receptors. In situ hybridization revealed expression of full-length trkB receptors in virtually all RSNs, which declined 7 d after axotomy. Full-length trkC mRNA was expressed at low levels. Using RT-PCR, we found that mRNAs encoding trkC isoforms with kinase domain inserts were present at levels comparable to that for the unmodified receptor. TrkA mRNA expression was not detected in RSNs, and the expression of p75 was restricted to a small subpopulation of axotomized cells. In agreement with the pattern of trk receptor expression, infusion of recombinant human BDNF or NT-4/5 into the vicinity of the axotomized RSNs, between days 7 and 14 after axotomy, fully prevented their atrophy. This effect was still evident 2 weeks after the termination of BDNF treatment. Moreover, BDNF or NT-4/5 treatment stimulated the expression of GAP-43 and Tα1-tubulin mRNA and maintained the level of trkB expression. Vehicle, NGF, or NT-3 treatment had no significant effect on cell size or GAP-43 and Tα1-tubulin expression. In a separate experiment, infusion of BDNF also was found to increase the number of axotomized RSNs that regenerated into a peripheral nerve graft. Thus, in BDNF-treated animals, the prevention of neuronal atrophy and the stimulation GAP-43 and Tα1-tubulin expression is correlated with an increased regenerative capacity of axotomized RSNs.
Objective: To test whether infusion of recombinant neurotrophic factors (BDNF, NT-4/5, NGF, or NT-3) prevents atrophy of axotomized rubrospinal neurons, stimulates regeneration-associated gene expression (GAP-43 and Tα1-tubulin mRNA), and promotes axonal regeneration into peripheral nerve grafts
This is a Cervical Axotomy with Neurotrophic Factor Infusion protocol using rat as the model organism. The procedure involves 7 procedural steps, 1 equipment items, 6 materials. Extracted from a 1997 paper published in Journal of Neuroscience.
Model and subjects
rat • not specified • unknown • not specified • not specified
Study window
~2 week study window
Core workflow
Cervical axotomy of rubrospinal neurons • Analyze trk receptor expression in axotomized RSNs • Perform RT-PCR analysis of trkC isoforms
Primary readouts
Key equipment and reagents
Verified items
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Perform surgical cervical axotomy to axotomize rubrospinal neurons
Note: This is the initial injury procedure that triggers the experimental timeline
“Rubrospinal neurons (RSNs) undergo a marked atrophy in the second week after cervical axotomy”
Perform in situ hybridization to determine expression patterns of trk family neurotrophin receptors in rubrospinal neurons
Note: Full-length trkB receptors expressed in virtually all RSNs; expression declined 7 days after axotomy. Full-length trkC mRNA expressed at low levels. TrkA mRNA not detected. p75 expression restricted to small subpopulation
“In situ hybridization revealed expression of full-length trkB receptors in virtually all RSNs, which declined 7 d after axotomy”
Use RT-PCR to detect mRNAs encoding trkC isoforms with kinase domain inserts
Note: trkC isoforms with kinase domain inserts present at levels comparable to unmodified receptor
“Using RT-PCR, we found that mRNAs encoding trkC isoforms with kinase domain inserts were present at levels comparable to that for the unmodified receptor”
Infuse recombinant human BDNF, NT-4/5, NGF, NT-3, or vehicle control into the vicinity of axotomized rubrospinal neurons
Note: Infusion period spans from day 7 to day 14 post-axotomy, during the period when atrophy typically occurs
“infusion of recombinant human BDNF or NT-4/5 into the vicinity of the axotomized RSNs, between days 7 and 14 after axotomy”
Measure cell body size of rubrospinal neurons to determine if atrophy was prevented
Note: BDNF or NT-4/5 treatment fully prevented atrophy; effect still evident 2 weeks after treatment termination. Vehicle, NGF, or NT-3 had no significant effect
“infusion of recombinant human BDNF or NT-4/5 into the vicinity of the axotomized RSNs, between days 7 and 14 after axotomy, fully prevented their atrophy. This effect was still evident 2 weeks after the termination of BDNF treatment”
Measure expression levels of regeneration-associated genes GAP-43 and Tα1-tubulin mRNA in treated and control neurons
Note: BDNF or NT-4/5 treatment stimulated expression of both genes and maintained trkB expression. Vehicle, NGF, or NT-3 had no significant effect
“BDNF or NT-4/5 treatment stimulated the expression of GAP-43 and Tα1-tubulin mRNA and maintained the level of trkB expression”
In a separate experiment, quantify the number of axotomized rubrospinal neurons that regenerated into a peripheral nerve graft
Note: BDNF infusion increased the number of axotomized RSNs that regenerated into peripheral nerve grafts
“infusion of BDNF also was found to increase the number of axotomized RSNs that regenerated into a peripheral nerve graft”
This section explains what the experiment is doing, which readouts matter, what the data artifacts usually look like, and how the analysis should flow from raw capture to reported result.
To test whether infusion of recombinant neurotrophic factors (BDNF, NT-4/5, NGF, or NT-3) prevents atrophy of axotomized rubrospinal neurons, stimulates regeneration-associated gene expression (GAP-43 and Tα1-tubulin mRNA), and promotes axonal regeneration into peripheral nerve grafts
Objective
To test whether infusion of recombinant neurotrophic factors (BDNF, NT-4/5, NGF, or NT-3) prevents atrophy of axotomized rubrospinal neurons, stimulates regeneration-associated gene expression (GAP-43 and Tα1-tubulin mRNA), and promotes axonal regeneration into peripheral nerve grafts
Subjects
From paperrat • not specified • unknown • not specified • not specified
Cohort notes
From paperRubrospinal neurons (RSNs) were the target neurons for study
Cervical axotomy of rubrospinal neurons (not specified)
Analyze trk receptor expression in axotomized RSNs (not specified)
Perform RT-PCR analysis of trkC isoforms (not specified)
Begin neurotrophic factor infusion (Between days 7 and 14 after axotomy)
Rubrospinal neuron cell body size (atrophy prevention)
From paperIn situ hybridization used to analyze mRNA expression patterns; RT-PCR used to detect trkC isoforms; cell size measurements and regeneration counts quantified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
GAP-43 mRNA expression levels
From paperIn situ hybridization used to analyze mRNA expression patterns; RT-PCR used to detect trkC isoforms; cell size measurements and regeneration counts quantified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Tα1-tubulin mRNA expression levels
From paperIn situ hybridization used to analyze mRNA expression patterns; RT-PCR used to detect trkC isoforms; cell size measurements and regeneration counts quantified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
TrkB receptor expression levels
From paperIn situ hybridization used to analyze mRNA expression patterns; RT-PCR used to detect trkC isoforms; cell size measurements and regeneration counts quantified
Artifact type
Endpoint measurements summarized by group or timepoint
Comparison focus
Compare endpoint magnitude between groups, timepoints, or both
Rubrospinal neuron cell body size (atrophy prevention)
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
GAP-43 mRNA expression levels
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Tα1-tubulin mRNA expression levels
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
TrkB receptor expression levels
From paperRaw artifact
Per-sample or per-animal endpoint measurements collected during the experiment
Processed artifact
Structured table with cleaned measurements ready for comparison
Final reported form
Summary statistics and between-group or across-timepoint comparisons
Acquisition
Collect raw experimental outputs with enough metadata to preserve sample identity, condition, and timing.
Preprocessing / cleaning
In situ hybridization used to analyze mRNA expression patterns; RT-PCR used to detect trkC isoforms; cell size measurements and regeneration counts quantified
Scoring or quantification
Quantify the primary readouts for this experiment: Rubrospinal neuron cell body size (atrophy prevention); GAP-43 mRNA expression levels; Tα1-tubulin mRNA expression levels; TrkB receptor expression levels.
Statistical comparison
Statistical method not yet structured for this page.
Reporting output
Report representative outputs alongside summary comparisons for Rubrospinal neuron cell body size (atrophy prevention), GAP-43 mRNA expression levels, Tα1-tubulin mRNA expression levels, TrkB receptor expression levels.
Source links and direct wording from the methods section for validation and deeper review.
Citation
Nao R. Kobayashi et al. (1997). BDNF and NT-4/5 Prevent Atrophy of Rat Rubrospinal Neurons after Cervical Axotomy, Stimulate GAP-43 and Tα1-Tubulin mRNA Expression, and Promote Axonal Regeneration. Journal of Neuroscience
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