Mild moxibustion at different intervention times on the levels of ET-1 and NO in the uterine tissues of rats with cold-damp coagulation and stagnation type dysmenorrhea

Objective： To observe the differences in analgesic effect of moxibustion at different intervention times on dysmenorrhea rats and explore its effect mechanism.Methods： Forty-five female Wistar rats were randomly divided into blank control group（group A）, model group（group B）, pre-moxibustion group（group C）, instant moxibustion group（group D） and pre-instant moxibustion group（group E）,with 9 rats in each group. Cold-damp coagulation and stagnation type dysmenorrhea models were established. In group C,mild moxibustion on ＂Shenque（神阙 CV 8） ＂ and＂Guanyuan（关元 CV 4）＂ was carried out from the time after modeling on the 8 th day for 3 consecutive days. In group D, mild moxibustion was given as the same methods with group C after injection with oxytocin on the 11 th day. In group E, mild moxibustion was given as the same methods from the time after modeling on the 8 th day to that after injection with oxytocin on the 11 th day for 4 consecutive days. The writhing behavior and the changes in levels of ET-1 and NO in uterine tissues of rats with dysmenorrhea in each group were observed.Results： Comparison of the latent period： compared with（4.38 ± 1.06） min in group B,the latent period of rats in group C（9.67 ± 1.32） min,group D（11.78 ± 1.30） min and group E（15.00 ± 1.22） min obviously prolonged（all p 0.01）. Compared with group C, the latent period of group E obviously prolonged（p 0.01）. Compared with group D, the latent period of group E obviously prolonged（p 0.01）.Comparison of the writhing times： compared with（4.38 ± 1.06） in group B,the writhing times of rats in group C（9.67 ± 1.32）,group D（11.78 ± 1.30） and group E（15.00 ± 1.22） reduced（all p 0.01）. Compared with group C,the writhing times of rats in group D and group E reduced（both p 0.01）. Compared with group D, the writhing times in group E reduced（p 0.05）. Comparison of the total writhing score：compared with（4.38 ± 1.06） in group B,the total writhing score of rats in group C（9.67±1.32）,group D（11.78 ± 1.30） and group E（15.00 ± 1.22） decreased（all p 0.01）. Compared with group C,the total writhing score of rats in group D and group E decreased（both p 0.01）. Compared with group D,the total writhing score of rats in group E decreased（p 0.05）. Comparison of ET-1 level： compared with（4.80 ± 0.47） in group A,the ET-1 level in uterine tissues of rats in group B（7.57±0.69） significantly increased（P 0.01）. Compared with group B, the ET-1 level in uterine tissues of rats in group C（6.20 ±0.50）,group D（5.67 ±0.29） and group E（5.16±0.33） obviously decreased（all p 0.01）. Compared with group C, the ET-1 level in uterine tissues of rats in group D and group E obviously decreased（p 0.05, p 0.01）. Compared with group D, the ET-1 level in uterine tissues of rats in group Eobviously decreased（p 0.05）. Comparison of NO level： compared with（6.63±1.83） in group A, the NO level in uterine tissues of rats in group B（1.62 ±0.58） significantly decreased（p 0.01）. Compared with group B, the NO level in uterine tissues of rats in group C（3.60±0.59）,group D（4.77 ±0.67） and group E（5.99±0.63） obviously increased（all p 0.01）. Compared with group C,the NO level in uterine tissues of rats in group Dand group E obviously increased（p 0.05, p 0.01）. Compared with group D, the NO level in uterine tissues of rats in group E obviously increased（p 0.01）.Conclusion： The analgesic effect of mild moxibustion at different intervention times on cold-damp coagulation and stagnation type dysmenorrhea rats was different, which was the most significant in pre-instant moxibustion group. One of the mechanisms of action may be related with the adjustment of abnormal levels of ET-1 and NO.