Liquor-nerve barrier permeability in the spinal nerve roots and dorsal root ganglia indicated by fluorescent-conjugated dextran
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| Year of publication | 2013 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | Diffusion of the molecules from liquor to the spinal nerve roots (SNR) and dorsal root ganglia (DRG) is one of possible way how is the neuroinflammation spread to the primary sensory neurons. The aim of our study was to demonstrate the diffusion capacity of fluorescent-conjugated dextran (FluoroRuby, FR; FluoroEmerald, FE) from liquor in subarachnoid space to DRG and SNR of cervical and lumbar segments. Ten Wistar rats (male, 250-300g) were used in our experiments after anesthesia with a mixture of ketamine and xylazine. In first group of animals (n=5), FR or FE was applied intrathecally to the cisterna magna and to the cisterna lumbalis in the second group of animals (n=5). After 18-24 hrs, the rats were deeply anaesthetized, perfused transcardially by Zamboni fixative and DRG together with their SNR were removed. Distribution of FR and FE was observed on cryostat sections and simultaneously the immunohistochemical reactions for resident (ED2) and activated (ED1) macrophages, satellite glial cells (GFAP, GS), proliferating cells (Ki-67), antigen presenting cells (MHC-II) and chemokine MCP-1 were performed. Strong red or green fluorescence present in SNR and DRG demonstrated diffusion of fluorescent-conjugated dextran from liquor. Fluorescence of FR or FE was localized in the satellite glial cells and neurons of DRG at the level of their application. The intensity of dextran fluorescence was higher in cervical DRG after lumbar application of FR/FE than in lumbar DRG after cervical application. In addition, diffusion of FR/FE from intrathecal space into DRG caused strong immune reaction presented by ED1+ macrophages and increased immunofluorescence for MHC-II a MCP-1. The dextran particles were localized in interstitial spaces of SNR, but in comparison with DRG the fluorescence intensity was significantly lower. Our results showed an easy diffusion of molecules from liquor to DRG and SNR. This indicates that neuroinflammatory mediators can spread by the road of intrathecal space from the point of origin to remote DRG and SNR. |
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