Objective To explore the specific mechanism of heat-reinforcing needling(HRN)for rheumatoid arthritis(RA)rabbits with cold syndrome based on metabolomics.Methods A total of 40 healthy rabbits were randomly divided into a normal group

a model group

a reinforcing-reducing needling(RRN)group

a twirling-reinforcing needling(TRN)group and a HRN group(n=8rabbits/group).The RA model with cold syndrome was established with ovalbumin and freezing.Except the normal and model groups

RRN

TRN and HRN were given at"Zusanli"(ST 36)in the corresponding acupuncture groups for 30 min

once a day for 7days.After the interventions

the pain threshold and the local skin temperature of each group were observed.The endogenous metabolites in the serum were analyzed by the gas chromatography mass spectrometry(GC-MS)technology combined with the pattern-recognition method.Results The pain threshold and the local skin temperature in the model group were lower than those in the normal group(P<0.05).The pain thresholds and the local skin temperatures in the three acupuncture groups were higher than those in the model group after interventions(P<0.05)

and those in the HRN group were obviously higher than those in the RRN and TRN groups(P<0.05).The serum metabolites of leucine

valine

isoleucine

and arachidonic acid in the model group were increased compared with those in the normal group(P<0.05)

and the metabolites ofα-ketoglutaric acid

citric acid

succinic acid

glucose

inositol

palmitic acid

stearic acid

lactose

d-ribose

and D-mannose were decreased(P<0.05).The above-mentioned metabolites in the three acupuncture groups were significantly reversed relevant to the model group(P<0.05)

and the effect of HRN group was significantly superior to those of the RRN and TRN groups in regulatingα-ketoglutaric acid

citric acid

succinic acid

glucose

inositol

d-ribose

and D-mannose(P<0.05).Conclusion HRN for RA with cold syndrome is effective

which may be related to the specific regulation for the krebs cycle and glycometabolism.