Comparison of analgesic effect of Huamoyan Keli between two strains of mice

Abstract

Objective To compare the analgesic effect ofHuamoyan Keli（HMYKL） between Kunming mice and BALB/c mice.Methods Eighty Kunming mice and eighty BALB/c mice were randomly divided into five groups, respectively： a control group, a ibuprofen group, a HMYKL high-dose group（13.98 g crude dru g/kg）, HMYKL middle-dose group（6.99 g crude drug/kg）and a HMYKL low-dose group（3.50 g crude dru g/kg）. There were 16 mice in each group with 8 male mice and 8 female mice. Drugs were administered intragastrically daily for 5 days. After 1 h of drug treatment on day 4, the latency of tail-flick response was evaluated using illuminated pain measurement instrument. After the last drug treatment, pain model was established by i.p. acetic acid, writhing latency and writhing times were recorded to evaluate the analgesic effect of HMYKL.Results In tail-flick test, there was no statistical difference among male and female Kunming mice in the HMYKL groups. Among male BALB/c mice, the latency in HMYKL middle-dose group was significantly longer than that in the control group（4.84±1.16 minvs. 3.93±0.76 min,P〈0.05）. In writhing test, compared with control group（19.06±6.34）, the writhing times among BALB/c mice were decreased in HMYKL high-dose group（8.56±6.19）, HMYKL middle-dose group（5.73±3.17）, HMYKL low-dose group（6.88±4.59）（allP〈0.01）.Conclusion All dose groups of HMYKL showed good analgesic effect on the pain induced by chemical stimulation and there was no sex difference. Kunming mice were not suitable for the evaluation of the analgesic pharmacodynamics because of their large individual difference. On contrast, BALB/c mice which had less individual difference could be used to produce the model of pain. Key words: Humoyan Keli; Analgesics （TCD） ; Pain