摘要Objective:To investigate the effect of internal heat acupuncture on the tolerance time of plantar hot plate and the pain threshold of gastrocnemius in rats with chronic myofascial pain syndrome(MPS).Methods:A total of 80 adult Wistar rats were randomly selected to establish chronic MPS rat models,and randomly divided into four groups:control group,acupuncture group,internal heat acupuncture group A,and inter-nal heat acupuncture group B,with 20 rats in each group.The rats in the control group were not given any treatment,and the rats in the acupuncture group were only given acupuncture treatment.The rats in group A were treated with internal heat acupuncture(needle heating up to 42 ℃),and the rats in group B were treated with internal heat acupuncture(needle heating up to 44℃).The tolerance time of plantar hot plate,the pain threshold of gastrocnemius muscle and the level of tumor necrosis factor-α(TNF-α)were observed and compared before modeling,1 d before treatment,and 1,7 and 14 d after treatment.Results:There were significant differences in hot plate tolerance time,time and interaction among the four groups(P＜0.05),as well as in gastrocnemius tenderness threshold,time and interaction among the four groups(P＜0.05),and there were also sig-nificant differences in TNF-α level among the three groups(P＞0.05).There were signifi-cant differences in the number of electric shocks,time and interaction among the four groups(P＜0.05).Conclusion:In contrast to conventional acupuncture treatment,internal heat acupuncture demonstrates greater efficacy in extending the tolerance duration of hot plate exposure and enhancing the pain threshold of the gastrocnemius muscle in rats af-flicted with myofascial pain syndrome.Additionally,it accelerates the amelioration of in-flammatory markers and motor function.However,it is important to note that the thera-peutic impact of internal heat acupuncture may be influenced by its temperature,with 44 ℃ being the most effective in this research.