Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neuronsReport as inadecuate




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BMC Neuroscience

, 7:8

First Online: 24 January 2006Received: 27 June 2005Accepted: 24 January 2006

Abstract

BackgroundInflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide LPS was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 a microglia and macrophage marker. Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation.

ResultsApplication of LPS induced a gradient of inflammation through the full depth of the motor cortex and promoted c-Jun and SCG10 expression for up to 2 weeks, and GAP-43 upregulation for 3 days by many corticospinal neurons, but had very limited effects on neuronal ATF3 expression. However, many glial cells in the subcortical white matter upregulated ATF3. LPS did not promote sprouting of anterogradely labelled corticospinal axons, which did not grow into or beyond a cervical lesion site.

ConclusionInflammation produced by topical application of LPS promoted increased expression of some growth-associated genes in the cell bodies of corticospinal neurons, but was insufficient to promote regeneration of the corticospinal tract.

List of Abbreviations UsedABCAvidin Biotin Complex

BDABiotinylated Dextran Amine

BSABovine serum albumin

C4 4cervical vertebral level

C6 6cervical vertebral level

CNSCentral nervous system

CSFCerebrospinal fluid

CSTCorticospinal tract

CTBCholera toxin – Subunit B

DABCO 14-diazabicyclo2,2,2octane

DRGDorsal root ganglion

FGFluorogold

GFAPGlial fibrillary acidic protein

HRPHorseradish peroxidase

LPSLipopolysaccharide

PBSPhosphate-buffered saline

RGCRetinal ganglion cell

SCISpinal cord injury

SSCStandard saline citrate

TBSTris-buffered saline

TBSTTBS + Triton X-100 0.5%

TNTTBS + Tween 20 0.05%

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2202-7-8 contains supplementary material, which is available to authorized users.

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Author: MK Hossain-Ibrahim - K Rezajooi - JK MacNally - MRJ Mason - AR Lieberman - PN Anderson

Source: https://link.springer.com/



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