Objective To investigate the effect of acupuncture treatment on silencing the expression of Oonnexin 43 （Cx43）, and to study the analgesic mechanism of acupuncture treatment for primary dysmenorrhea （PD） in rats. Methods We used estrostilben to develop the model of primary dysmenorrhea in rat, and RNA interference technology to silence the expression of Cx43 in acupoints. Fifty female rats were randomly divided into five groups （n = 10 in each group） ： normal, model, acupuncture, acupuncture ＋ interference and acupuncture＋ interference control group, pSilencer-Cx43-shRNA and pSilencer-Oon-shRNA were injected locally into the acupoints in interference group and interference-control group, respectively. The incidence rate of writhe reaction over the period of 30 min was evaluated. The expression of the oxytocin receptor （OTR） and vasopressin receptor（VasR） in rat myometrium with Semiquantitative RT-POR and immunohistochemistry. Results （1）The mRNA and protein level of Cx43 in acupoints in interference group were significantly lower those of in the acupuncture group （P〈0.05）. There was no significant difference between acupuncture and interference-control group. （2） Acupuncture could significantly prolong the latency period of writhing body and decrease the number of writhing body as compared with that of model group and interference group. （3）The level of OTR and VasR mRNA and protein in the model group were significantly higher （P〈0.05） as compared to normal group. The results in acupuncture group and interference-control group were similar to the normal group. The results in interference group were similar to the model group. Conclusions Acupuncture may be useful in the treatment of the model of primary dysmenorrhea in the rats. Local injection of Cx43 shRNA expression vetor could silence the expression of Cx43 in acupoint and markedly influence acupuncture effect, demonstrating Cx43 is involved in acupuncture effect.
