Abstract: Objective To evaluate the analgesic effect of tongjingting paste in rats model with experimental dysmenorrhea and to reveal its analgesic mechanism. Methods The experimental dysmenorrheal model in rats was induced with oxytocin. A writhing test was employed to evaluate the analgesic effects of tongjingting paste, which was designed into different doses, in animal subjects. The contents of 6-keto-PGF1α in the blood plasma were observed by ELISA assay. Results Tongjingting paste has a significant analgesic effect on experimental dysmenorrheal model in rats. Latent period was delayed significantly, the number of writhing response was evidently decreased as well. Besides, 6-keto-PGF1¦Á were significantly increased in the treated groups. Conclusion Tongjingting paste had a significant analgesic effect on experimental dysmenorrheal model in rats. Its analgesic mechanism may be mediated by regulating the plasma levels of 6-keto-PGF1α.

Key words: Tongjingting paste, Experimental dysmenorrheal, Writhing reaction, 6-keto-PGF1α, Rat