Intrathecal Resiniferatoxin Modulates TRPV1 in DRG Neurons and Reduces TNF-Induced Pain-Related Behavior

Figure 3

Influence of intrathecal administration of TNF and TNF + RTX on the protein level of TRPV1 and the number of TRPV1-expressing DRG neurons. (a) Immunohistochemical staining of DRG slices 24 h after administration of either 200 ng/kg TNF, 1.9 μg/kg RTX, or 200 ng/kg TNF + 1.9 μg/kg RTX. DRG neurons were stained against NeuN (red), as a neuronal marker and TRPV1 (green). Quantification of TRPV1-derived signals revealed significant increase in TRPV1 protein level after TNF administration, (), while administration RTX decreased the TRPV1 protein level significantly (), compared to control conditions. When TNF and TRPV1 were administrated together, a significant change to sole TNF administration was observed. Combined administration of TNF and RTX abolished the TNF-mediated increase of the TRPV1 protein level (). No significant change was observed when compared to untreated control (). In addition to the protein level of TRPV1, the number of TRPV1-expressing neurons within the DRG was significantly increased after TNF administration, compared to control conditions (). RTX administration significantly decreased the number of TRPV1-expressing neurons (). Combined application of TNF + RTX led to a significant reduction of TRPV1-positive neurons, compared to TNF administration (). When compared to control conditions, no significant alteration in the number of TRPV1-expressing neurons was observed (). (b) Western blot analysis showed an increase of TRPV1 protein level 24 h after TNF administration (), while additional administration of RTX reduced this effect ().

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