Objective To observe the analgesic effect of heat-reinforcing needling manipulation for acute inflammatory arthritis and its underlying mechanism in experimental rheumatoid arthritis rabbits.Methods A total of 60 rabbits were randomized into control(n=6)

model(n=6)

needle-twirling(n=24) and heat-reinforcing(n=24) groups

and the later 2 groups were further divided into 0 h

0.5 h

1 h and 2 h subgroups

with 6 cases in each.Rheumatoid arthritis model was established by injecting mixed solution of egg-albumin(4 mg/ml) and equal volume of complete Freund's adjuvant(CFA) into the subcutaneous tissue(6 points around the shoulder

0.2 ml/point).Fourteen days later

the injection was repeated once again

and another 6 days later

egg-albumin(0.4 ml

20 mg/ml) solution was injected into the bilateral knee-joints."Zusanli"(ST 36) and "Hegu"(LI 4) were punctured and stimulated by needle-twirling or by heat-reinforcing needling technique for 1 min

with the needle retained for 30 min.The pain threshold of the paw was detected with K+import stimulation method.β-EP and PGE2 contents of the joint tissue were assayed with radioimmunoassay.Results Compared with model group

the pain threshold of needle-twirling group and heat-reinforcing group at each time-point increased significantly(P<0.01

P<0.05).Compared with needle-twirling group

the pain threshold of heat-reinforcing group at 0.5 h

1 h and 2 h subgroups increased significantly(P<0.05

P<0.01).Both β-EP and PGE2 contents of model group were significantly higher than those of control group(P<0.01

P<0.05).In comparison with model group

β-EP contents of needle-twirling group and heat-reinforcing group at each time-point increased significantly(P<0.01

P<0.05)

and PGE2 contents of needle-twirling group and heat-reinforcing group at each time-point decreased significantly(P<0.01

P<0.05).The β-EP content of heat-reinforcing group was significantly higher than that of needle-twirling group at 2 h(P<0.05)

while PGE2 content of the former group was significantly lower than that of needle-twirling group at 0 h(P<0.01).Conclusion Both needle-twirling and heat-reinforcing needling can effectively raise the pain threshold in acute arthritis rabbits

which my be closely associated with their effects in upregulating β-EP content and lowering PGE2 level in the local joint tissue.The analgesic effect of heat-reinforcing needling manipulation is superior to that of needle-twirling.