Objective: To observe and compare the effects of different acupuncture and moxibustionmethods at “San-yinjiao” (SP6) on uterine contraction and microcirculation in cold congealing dysmenorrhea rats, so as to explore its mechanism underlying treatment of dysmenorrhea.
Methods: A total of 140 female SD rats were randomly divided into normal control, mo-del, perpendicular needling, transverse needling and moxibustion groups, with 28 rats in each group. The cold congealing dysme-norrhea rat model was prepared by exposure in a freezer (25 ℃) for 4 h, once daily for 5 days, and subcutaneous injection of estradiol benzoate (once daily for 10 days) and intra-abdominal injection of oxytocin (once).
For rats in three intervention groups, acupuncture needles were inserted into bilateral Sanyinjiao (SP 6) perpendicularly or transversely to a depth of 4~5 mm and retained for 20 min, or moxibustion was applied to Sanyinjiao (SP 6) for 20 min. The uterine contraction degree and the uterine microcirculation were recorded. The expression levels of transient receptor potential vanilloid 1 (TRPV1) and heat shock protein 70 (HSP70) in local tissues of Sanyinjiao (SP 6) area were detected by immunohistochemistry. The expression levels of μopioid receptor and endothelin 1 (ET1) mRNA in the uterus were assessed by quantitative real time-PCR.
Results: After modeling and compared with the normal control group, the number and peak-to-peak values of uterine contraction waves, and uterine motility were significantly increased (P<0.01,P<0.05), while the speed of blood flow in the microvessels was slowed down (P<0.01), diameters of the uterine microvessels and capillaries (cap) shrank obviously (P<0.01) in the model group. After the intervention, all indexes of uterine contraction and microcirculation were improved in three intervention groups (P<0.01, P<0.05), while transverse needling and moxibustion showed better effects compared to perpendicular needling (P<0.05, P<0.01).
The expression of TRPV1 and HSP70 in SP 6 area had no significant changes (P>0.05), while the uterine μopioid receptor mRNA expression decreased (P<0.01), and ET1 mRNA expression increased (P<0.01) in the model group relevant to the normal control group. Following the intervention, the expression levels of TRPV1 and HSP70 in SP6 area were increased (P<0.05, P<0.01), and expression levels of uterine μopioid receptor mRNA increased (P<0.05, P<0.01) and uterine ET1 mRNA decreased (P<0.05, P<0.01) in the three intervention groups. The effect of moxibustion was considerably better than those of two acupuncture groups in up-regulating TRPV1 expression (P<0.05). Both transverse needling and moxibustion showed better effects of down-regulating uterine ET1 mRNA expression than perpendicular needling (P<0.01).
Conclusion: Transverse needling and moxibustion at Sanyinjiao (SP 6) have a better effect of relieving uterine contraction and improving uterine microcirculation than perpendicular needling, which may be related to their effects in up-re-gulating the expression of TRPV1 and HSP70 in Sanyinjiao (SP 6) area, thereby modulating the mRNA expression of μ opioid receptor and ET1 in uterine tissue.