Antinociceptive effects of matrine on neuropathic pain induced by chronic constriction injury.

Context: Sophora alopecuroides L. (Leguminosae) is a commonly used Chinese herbal drug that possesses antipyretic, anti-inflammatory and analgesic effects. Among various alkaloids isolated from S. alopecuroides, matrine has been identified as the major bioactive component contributing to a variety of pharmacological effects, and studies have also shown that matrine has an analgesic effect.

Objective: To investigate the antinociceptive effects of matrine on neuropathic pain induced by chronic constriction injury (CCI) in mice.

Materials And Methods: The von Frey, plantar, cold-plate, locomotor activity and rota-rod test were performed to assess the degree of mechanical, radiant, thermal, spontaneous locomotor activity and motor coordination changes respectively, at different time intervals, i.e., one day before surgery and 7, 8, 10, 12 and 14 days post surgery. Matrine was administered from the 8th day after the surgery for seven days.

Results: Our present study shows that matrine at the dose of 30 mg/kg i.p. increased the paw withdrawal threshold (0.88 ± 0.16), paw withdrawal latency (7.01 ± 0.11) and the counts of paw withdrawal (19.7 ± 1.15) from the day 8 for the nerve injured paw compared to the CCI group (0.18 ± 0.04, 4.62 ± 0.18, 44.3 ± 2.99, respectively). Matrine, in a dose-dependent effect, was also found to produce a protective role in both plantar and cold-plate tests. The analysis of the effect supports the hypothesis that matrine is useful in neuropathic pain therapy.

Discussion And Conclusion: The results of this study suggest that matrine could be useful in the treatment of different kinds of neuropathic pains as an adjuvant to conventional medicines.