Genotoxicity Evaluation of Capsaicin-Containing (CP) Pharmacopuncture, in an In Vivo Micronucleus Test

Objectives: Capsaicin-containing (CP) pharmacopuncture was developed to treat neuropathic pain. This study was conducted to assess the toxicity of CP extract for pharmacopuncture, using a micronucleus test. Methods: First, a dose range finding study was conducted. Then an in vivo micronucleus test was performed to determine the induction of micronuclei in mouse bone marrow cells after intramuscular administration of CP twice with a 24-hour interval to 8-week-old ICR mice. A high dose of 0.2 mL/animal was selected, and this was sequentially diluted by applying a geometric ratio of 2 to produce two lower dose levels (0.1 and 0.05 mL/animal). In addition, negative and positive control groups were set up, and an HPLC analysis was conducted to confirm the capsaicin content of CP. Results: The incidence of micro-nucleated polychromatic erythrocytes in polychromatic erythrocytes in the CP-treated group was similar to that in the negative-control group, while that in the positive-control group was significantly greater. In addition, the ratio of polychromatic erythrocytes to total erythrocytes in the CP treatment group and the positive control group was not significantly different from the negative control group. In the HPLC analysis, capsaicin in the CP was identified through a comparison with the retention time of the capsaicin standard of 27 min. Conclusion: CP did not show any indication of any potential to induce micronuclei formation in bone marrow cells of ICR mice under the conditions of this study. Further toxicity studies are necessary to ensure the safety of the use of CP in clinical practice.