OBJECTIVETo compare the effects of different acupuncture methods on urine metabolites in rheumatoid arthritis (RA) rabbits, and to explore the specificity mechanism of heat-reinforcing acupuncture for RA.

METHODSA total of 40 clean purple-blue rabbits were randomly allocated to a normal group, a model group, a mild reinforcing-reducing needling (MRRN) group, a twirling-reinforcing needling (TRN) group and a heat-reinforcing needling (HRN) group, 8 rabbits in each one. Except the normal group, the rabbits in the remaining groups were treated with ovalbumin and freezing to establish RA model. The rabbits in the MRRN group, TRN group and HRN group were treated with MRRN, TRN and HRN at "Zusanli" (ST 36), respectively, 30 min per treatment, once a day for seven days. After treatment, 24-h urine was collected. The rabbits were sacrificed to collect synovial tissues of knee to perform morphology observation; the liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q/TOF-MS) was applied to measure urine metabolites. All the data were analyzed by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA).

RESULTSCompared with the normal group, the leucine-related metabolites, as main urine metabolites, were decreased in the model group (<0.05), while the purine-related metabolites and tryptophane-related metabolites were increased (<0.05). Compared with the model group, the leucine-related metabolites, as main urine metabolites, were increased in the three needling groups after treatment (<0.05), while the tryptophan-related metabolites andpurine-related metabolites were decreased (<0.05), moreover, the leucine-related metabolites in the HRN group were obviously higher than those in the MRRN group and TRN gruop (<0.05).

CONCLUSIONSMRRN, TRN and HRN can regulate the pathway of leucine metabolism (energy metabolism), purine metabolism (oxidative damage) and tryptophane metabolism (immune regulation) for RA, The specificity of HRN for RA focuses on regulation of leucine metabolism (energy metabolism).