Neuroprotective effects of an extract from the inflamed skin of rabbits inoculated with vaccinia virus on glutamate-induced neurotoxicity in cultured neuronal cell line.

Objective: Protein-free extracts from the inflamed skin of rabbits inoculated with vaccinia virus (Rosemorgen(R) and Neurotropin(R)) are widely employed to combat chronic pain and treat allergic conditions in human subjects in Japan. However, the pharmacologic mechanisms of Rosemorgen(R) and Neurotropin(R) remain unclear. Methods: In this study, we examined the effects of Rosemorgen(R) on L-glutamic acid (Glu)-induced cell death in N18-RE-105 neural cell line, which only possessed non-N-methyl-Daspartate (NMDA)-type receptors. Results: There were many large cytoplasmic cells and elongation of fivers in phosphate-buffered saline (PBS) additional group without Glu. In PBS and Glu simultaneous additional group, the survival ratio was decrease significantly compared with PBS alone group. Moreover, there were dead cells which did not have cytoplasm and aggregated nucleus. The Glu-induced cell death of N18-RE-105 cells was inhibited by both pre-treatment (24 hours before Glu treatment) and simultaneous treatment with Rosemorgen(R). There were many large cytoplasmic cells and elongation of fivers in Rosemorgen(R) group. Discussion: From this finding in N18-RE-105 cells, Rosemorgen(R) was concluded to inhibit Glu-induced cell death via non-NMDA type receptors. One of the pharmacologic mechanisms of Rosemorgen(R) has been clear. These results suggest that Rosemorgen(R) depresses allodynia and chronic pain through interaction with non-NMDA type receptors.