| ObjectiveThe objective of this study was to compare the effects of electroacupuncture(EA) at uterus-relevant acupoint(Sanyinjiao SP6, Xuehai SP10), uterus-irrelevant acupoint (Xuanzhong GB39)and non-meridian point in the same or similar spinal segments, on writhing response, uterine microcirculation and diastolic materials and contractive materials of uterine smooth muscle in dysmenorrhea model rats. EA was conducted on rats instantly and beforehand, so as to investigate its mechanism on primary dysmenorrhea (PD), the specificity of acupoints in regulating function of uterus, and the effect of interventiontime on specificity of acupoints. As an experimental study, the purpose of this study is to provide experimental evidence for revealing the mechanism of EA for PD and the affecting factors of acupoint specificity. Simultaneously, this study also aimed at providing scientific guidance for selection of acupoints and determination of intervention time of EA for PD in the clinic.Methods192 diestrus SD female rats were randomly divided into instant saline(IS) group, instant model (IM) group, instant Sanyinjiao (ISP6) group, instant Xuehai(ISP10), instant Xuanzhong (IGB39) group, instant non-meridian point (INP) group and pre-saline (PS) group, pre-model (PM) group, pre-Sanyinjiao (PSP6) group, pre-Xuehai(PSP10), pre-Xuanzhong (PGB39)group, pre-non-meridian point (PNP) group according to the intervention time of EA, with 16 rats in each. Except saline group, the rats in other groups were subcutaneous injection of estradiol benzoate for 10 days continuously, and intraperitoneal injected with oxytocin 1h after the last estradiol injection to establish dysmenorrhea rat model. Rats in four instant EA groups received EA for 20 min after injection of oxytocin. On the 8th day after subcutaneous injection of estradiol benzoate, rats in four pre-EA groups received 3 treatment sessions, each of 20-min duration, once a day for 3 days, saline group and model group were not treated with EA. In the first experiment, writhing responses of rats in instant EA groups were observed with EA, while the writhing responses in pre-EA groups were observed after injection of oxytocin in the last EA session. The latency period and score of writhing were recorded for 20 minutes in each group. In the second experiment, changes of uterine microcirculation were observed by using a Cold Light Microcirculation Detector at the time points of 5min, 10min,20min with EA in instant EA groups, while uterine microcirculation in pre-EA groups were observed after injection of oxytocin in the last EA session, the study points were same as instant EA groups. In the third experiment, the content of Plasma TXB2.6-keto-PGF1αwere detected with radioimmunoassay after recording the writhing responses, the content of ET was measured by ELISA and the content of NO was measured by chemiluminescene assay after uterine microcirculation was observed. Results1 Effects of different intervention time of EA on writhing response of dysmenorrhea model ratsIn six instant groups:Compared with saline group, the latency period of writhing in model group was shortened significantly (P<0.01),and the writhing score was increased significantly (P<0.01). In comparison with model group, the latency period of writhing was lengthened significantly in ISP6 group(P<0.05), the writhing score were decreased significantly in four instant EA groups(P<0.01). There were no significant differences in latency period and score of writhing between every two of the four instant EA groups (P>0.05).In six prepare groups:Compared with saline group, the latency period of writhing in model group was shortened significantly(P<0.01), and the writhing score was increased significantly (P<0.05). In comparison with model group, there were no significant differences of the latency period and score of writhing in all instant EA groups (P>0.05).The writhing score in PSP6 group was significantly increased compared with PSP10 group and PNP group(P<0.05).2 Effects of different intervention time of EA on uterine microcirculation of dysmenorrhea model ratsIn six instant groups:Compared with saline group, diameters of microvessels and capillaries in model group were shrinked(P<0.01), numbers of microvessels and capillaries were decreased significantly(P<0.05, P<0.01), articulation indexes of microvessels and capillaries were reduced(P<0.01), the color of microvessels became deepen(P<0.01), the blood flow was slow and even stopped(P<0.01). Compared with model group, diameters of microvessels and capillaries were expanded significantly, numbers of microvessels and capillaries were increased significantly, the color of microvessels was improved at the time point 20min after EA in the ISP6 group(P<0.05), articulation indexes of microvessels and capillaries were improved significantly at the time points of 5min, 10min,20min after EA ISP6(P<0.01, P<0.05, P<0.01, P<0.05), there was no significant difference in the state of blood flow in the ISP6 group(P>0.05), articulation indexes of microvessels and capillaries, the color of microvessels were improved at 20min after EA in the IGB39 group(P<0.05), while there wasn't significant difference in each indicator after EA on ISP10,INP(P>0.05). The articulation index of microvessels of ISP6 group was significantly improved than that of the ISP10,IGB39 and INP group at the time point 5min(P<0.05, P<0.01), the diameter of uterus capillaries of ISP6 group was significantly bigger than that of the INP group at the time point 20min(P<.05).In six prepare groups:Compared with saline group, diameters of microvessels and capillaries in model group were shrinked(P<0.01), numbers of microvessels and capillaries were decreased significantly(P<0.01, P<0.05, P<0.01), articulation indexes of microvessels and capillaries were reduced(P<0.01), the color of microvessels became deepen(P<0.01), the blood flow was slow and even stopped(P<0.01). Compared with model group, diameters of microvessels and capillaries(except 5min)were expanded significantly(P<0.01, P<0.05, P<0.01), numbers of microvessels and capillaries (except5min,10min)were increased significantly(P<0.05), articulation index of microvessels and capillaries(except 5min), the color of microvessels(except 5min) was improved and the state of blood flow sped up after EA PSP6 at the time points of 5min, 10min,20min, diameters of microvessels and capillaries(except 5min,10min)were significantly expanded(P<0.05, P<0.01, P<0.05), numbers of microvessels were increased significantly(P<0.05), articulation index of microvessels and capillaries(except 5min, lOmin). color of microvessels(except 5min,10min) were improved(P<0.01, P<0.05) after EA PGB39 at the time points of 5min, 10min,20min, articulation index of capillaries was improved after EA PSP10 at the time point 20min(P<0.05), articulation index of microvessels was improved after EA PNP at the time points of lOmin,20min(P<0.05). Diameters of microvessels were expanded significantly(P<0.01), articulation index of microvessels was improved significantly of PSP6 group, PGB39 group than that of PSP10 group at the time points of 5min, 10min, 20min(P<0.01, P<0.05), numbers of microvessels were increased significantly of PSP6 group than that of PSP10 group at the time point 10min(P<0.05), blood flow sped up of PSP6 group than that of PSP10 group at the time points of 5min, 10min,20min(P<0.05), diameters of microvessels were expanded significantly of PSP6 group, PGB39 group than that of PNP group at the time points of 5min,10min,20min(P<0.01), numbers of capillaries were increased significantly of PSP6 group. PGB39 group than that of PNP group at the time point 20min(P<0.05), blood flow sped up of PSP6 group than that of PNP group at the time points of 10min,20min(P<0.05).3 Effects of different intervention time of EA on diastolic materials and contractive materials of uterine smooth muscle of dysmenorrhea model ratsIn six instant groups:①lasma indexes:Compared with saline group, the content of plasma TXB2,and the ratio of TXB2/6-keto-PGF1αin model group were increased significantly(P<0.01). In comparison with model group, the content of plasma TXB2 and TXB2/6-keto-PGF1αin four EA groups were decreased significantly(P<0.05, P<0.01), the content of plasma 6-keto-PGF1αin PSP6 group was increased significantly(P<0.05).②terine indexes:Compared with saline group, the content of uterine NO in model group was increased significantly(P<0.01), the ratio of ET/NO was decreased significantly(P<0.01). In comparison with model group, the content of uterine NO in four EA group(except PNP group) were decreased significantly(P<0.05), the ratio of ET/NO in four EA group were increased significantly(P<0.01, P<0.05).In six prepare groups:①lasma indexes:Compared with saline group, the content of plasma TXB2 and the ratio of TXB2/6-keto-PGF1αin model group were increased significantly(P<0.05). Compared with model group, the ratio of TXB2/6-keto-PGF1αin PSP6 group was decreased significantly(P<0.05).②terine indexes:Compared with saline group, the content of uterine NO in model group was increased significantly(P<0.01), the ratio of ET/NO was decreased significantly(P<0.01). In comparison with model group, the content of uterine NO was decreased significantly and the ratio of ET/NO was increased significantly in PSP6 group(P<0.01), the ratio of ET/NO was increased significantly in PGB39 group(P<0.01).The content of uterine NO was decreased significantly of PSP6 group than that of PSP10 group and PNP group, the ratio of was increased significantly than that of PNP group(P<0.05).Conclusions1 All study acupoints (SP6, SP10, GB39) and non-meridian point with instant EA showed analgesic effect in dysmenorrhea model rats, the effect of SP6 was most evident. SP6 showed preliminarily specificity for PD.2 Regulating diastolic materials and contractive materials of uterine smooth muscle by regulating nerve reflex to relieving spasm of uterine smooth muscle and uterine pain may be the main mechanism of analgesic effect of each acupoint with instant EA.3 Nor acupoints (SP6, SP10, GB39) or non-meridian point with pre-EA showed analgesic effect in dysmenorrhea model rats. However, SP6 showed better effect than SP10 and non-meridian point.4 Both instant EA and pre-EA can improve uterine microcirculation in dysmenorrhea model rats, but pre-EA had the better effect.5 SP6 showed most significant effect to improve uterine microcirculation in dysmenorrhea model rats with instant EA and pre-EA, compared with SP10, GB39 and non-meridian point. SP6 showed preliminarily specificity for PD.In summary, this study showed EA at different acu-points and intervention time may have different regulating effect and mechanism in PD. SP6 showed specificity for PD, and the specificity was relative. Instant EA had affirmative effect in relieving uterine pain, while pre-EA had affirmative effect in improving uterine microcirculation. Intervention time of acupuncture had certain influence on specificity of acupoint. |
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