We analyzed the effect of capsaicin on Schwann cells’ gene expression pattern, major histocompatibility complex class II (MHC-II) expression, and H₂O₂ induced oxidative stress. Furthermore, the effect of capsaicin on myelination was examined in a SC-dorsal root ganglia (DRG)-coculture by myelin basic protein staining. Finally, in order to investigate the isolated effect of capsaicin on SCs in EAN pathology, we transplant naïve and capsaicin pre-treated SCs intrathecally in EAN immunized rats and analyzed clinical presentation, electrophysiological parameters, and cytokine expression in the sciatic nerve.

In SC culture, incubation with capsaicin significantly reduces interferon gamma induced MHC-II production as well as toll-like receptor 4 and intercellular adhesion molecule 1 mRNA expression. Calcitonin gene-related peptide mRNA production is significantly up-regulated after capsaicin treatment. Capsaicin reduced H₂O₂ induced oxidative stress in SC in a preventive, but not therapeutic setting. In a SC-DRG-coculture, capsaicin does not affect myelination rate. After intrathecally transplantation of naïve and capsaicin pre-treated SCs in EAN immunized rats, naïve, but not capsaicin pre-treated intrathecally SCs ameliorated EAN pathology in rats.