Dose-Effect Response in Acupuncture for Functional Constipation

This is a single-center, randomized, parallel-group trial evaluating the dose-response relationship of two experimental interventions: manual acupuncture and electroacupuncture for functional constipation. A total of 72 participants with functional constipation (Rome IV criteria) will be randomly assigned in a 1:1 ratio to either the manual acupuncture group or the electroacupuncture group. Both groups receive acupuncture at bilateral Tianshu (ST25) and Shangjuxu (ST37) points, 30 minutes per session, three times per week for 12 weeks. The electroacupuncture group additionally receives electrical stimulation (continuous wave, 10 Hz, 0.5-4 mA). The primary outcome is the responder rate at week 12, defined as the percentage of participants with ≥3 complete spontaneous bowel movements (CSBMs) per week. Secondary outcomes include changes in gut microbiota, brain functional connectivity measured by multimodal MRI and fNIRS, and scales. The study aims to clarify the dose-response characteristics of different acupuncture modalities and their underlying biological mechanisms.