Objective: To investigate the effect of acupuncture on the brain functional activities of the patients with primary dysmenorrhea based on the resting-state functional magnetic resonance imaging (rs-fMRI), and to provide visual evidence for the central mechanism of acupuncture in treatment of primary dysmenorrhea.
Methods: Forty-two patients of primary dysmenorrhea were enrolled and randomly divided into an observation group (21 cases, 1 case dropped off) and a control group (21 cases, 2 cases dropped off, 3 cases withdrawal). In the observation group, acupuncture was exerted at Sanyinjiao (SP 6) and Guanyuan (CV 4), started 5-7 days before menstrual flow, once a day till menstrual onset, for a total of 3 menstrual cycles. No intervention was applied in the control group. The scores of visual analogue scale (VAS) and Cox menstrual symptom scale (CMSS) were observed in both groups before and after treatment. Based on rs-fMRI, the data of resting-state functional magnetic resonance were collected from two groups before and after treatment. Combined with functional connectivity strength (FCS) and functional connectivity (FC) analysis, the differences of brain regions before and after treatment were compared between the two groups and the correlation was analyzed between their functional connectivity changes and the improvements in VAS and CMSS scores of the patients in the observation group.
Results: In the observation group, the scores of VAS and CMSS were all decreased after treatment (P<0.05), while the scores related to the symptom time in CMSS was reduced in comparison with that before treatment in the control group (P<0.05). The score reducing ranges of VAS and CMSS in the observation group were larger than the control group (P<0.05). Compared before treatment, FCS of the right middle cingulate cortex and the left cuneus was increased, while FCS of the left inferior parietal lobule was decreased after treatment in the observation group. In the control group, FCS of the left orbital frontal cortex was increased after treatment. Compared with the control group, FCS of the left anterior insula was increased in the observation group after treatment. FC analysis was performed using the left anterior insula as the seed point. In comparison with the control group, FC of the left anterior insula was increased either with the inferior temporal gyrus or with the right hippocampus; and was decreased either with the middle occipital lobe or with the right dorsolateral prefrontal cortex in the observation group after treatment. In the observation group, FC between the left anterior insula and the right hippocampus was positively correlated with the improvements in symptom severity (r =0.385, P<0.05) and symptom time (r =0.510, P<0.05) of CMSS, and FC between the right dorsolateral prefrontal cortex and the left anterior insula was negatively correlated with the improvement in symptom severity of CMSS after treatment (r =-0.373, P<0.05).
Conclusion: The anterior insula may be the key brain region in treatment of primary dysmenorrhea with acupuncture. Acupuncture may relieve dysmenorrhea and the related symptoms through strengthening the functional connectivity of anterior insula-limbic system and anterior insula-control network.
目的：基于静息态功能磁共振成像（rs-fMRI），探讨针刺对原发性痛经（PDM）患者脑部功能活动的影响，为针刺治疗PDM的中枢机制提供可视化证据。方法：将42例PDM患者随机分为观察组（21例，脱落1例）和对照组（21例，脱落2例，剔除3例）。观察组予针刺三阴交、关元，于月经来潮前5~7 d开始治疗，每天1次至月经来潮为止，共治疗3个月经周期；对照组不进行任何治疗。观察两组治疗前后视觉模拟量表（VAS）评分和Cox痛经症状量表（CMSS）评分；基于rs-fMRI技术，于治疗前后采集两组患者静息态功能磁共振数据，联合全脑功能连接强度（FCS）和功能连接（FC）分析方法比较两组患者治疗前后差异脑区，并分析其功能连接改变与观察组患者VAS、CMSS评分改善值的相关性。结果：治疗后，观察组VAS、CMSS评分均较治疗前降低（P<0.05），对照组CMSS-持续时间评分较治疗前降低（P<0.05），观察组VAS、CMSS评分降低幅度大于对照组（P<0.05）。与治疗前比较，观察组治疗后右侧中扣带皮层和左侧楔叶FCS增高，左侧顶下小叶FCS降低，对照组左侧眶额叶FCS增高；观察组较对照组FCS增高的脑区为左侧前脑岛（AI）。以左侧AI为种子点进行FC分析，与对照组比较，治疗后观察组与左侧AI功能连接增高的脑区有颞下回、右侧海马，与左侧AI功能连接减弱的脑区有枕中叶、右侧背外侧前额叶皮质。观察组治疗后左侧AI-右侧海马脑功能连接与CMSS-严重程度评分改善值（r =0.385，P<0.05）及CMSS-持续时间评分改善值（r =0.510，P<0.05）呈正相关，左侧AI-右侧背外侧前额叶皮质与CMSS-严重程度评分改善值呈负相关（r =-0.373，P<0.05）。结论：AI可能是针刺治疗PDM的重点脑区，针刺可能通过加强AI-边缘系统和AI-控制网络的功能连接改善痛经及其伴随症状。.
Keywords: acupuncture; functional connectivity; functional connectivity strength; insula; primary dysmenorrhea.