RESUMO
<p><b>OBJECTIVE</b>To search the mechanism of Huaisanzhen in treating the nerve root pain caused by protrusion of lumbar intervertebra disc.</p><p><b>METHODS</b>Sixty male SD rats were randomly divided into a normal control group, a sham operation control group, a model control group, an aspirin-DL-lysine control group, a routine body acupuncture group, and a Huaisanzhen treatment group. The aspirin-DL-lysine control group, the routine body acupuncture group and the Huaisanzhen treatment group were treated by aspirin-DL-lysine through intramuscular injection, routine acupuncture and Huaisanzhen therapy, respectively. The pain threshold and the content of brain 5-HT in each group were determined.</p><p><b>RESULTS</b>The pain threshold significantly increased in the Huaisanzhen treatment group as compared with that in the model control group at the same hour points (P < 0.05). And at the 30 min, the pain threshold in the aspirin-DL-lysine control group and the routine body acupuncture group was significantly higher than that in the model control group, and the Huaisanzhen treatment group was significantly higher than that in the aspirin-DL-lysine control group and the routine body acupuncture group (all P < 0.05). The 5-HT contents at the same time in the Huaisanzhen treatment group were higher than those of the model control group and the aspirin-DL-lysine control group (P < 0.01). The 5-HT content at 30 min in the Huaisanzhen treatment groups was significantly higher than that of the routine body acupuncture group (P < 0.05).</p><p><b>CONCLUSION</b>The analgesic effect of Huaisanzhen treatment is closely related to increase of 5-HT content in the brain.</p>