Effects of Electroacupuncture at NP82 and SP15 on Bowel Motility in Healthy Subjects

Background and Rationale:

Bowel motility is a fundamental physiological function regulated by the autonomic nervous system. This study explores the potential of electroacupuncture (EA) to modulate this activity using a unique acupoint combination: Dai Hoanh (SP15), a classic point known for regulating the Spleen and Stomach, and Thong Tien (NP82), a newly proposed "extra point" specifically indicated for treating paralysis-related constipation in traditional literature. The study aims to provide the first modern scientific evidence for the effectiveness of NP82 in stimulating bowel motility.

Methodology:

The study follows a before-and-after intervention design involving 30 healthy volunteers. To ensure objective measurement, bowel sounds are recorded using the 3M™ Littmann® CORE Digital Stethoscope, which amplifies sounds and allows for computerized analysis, overcoming the subjectivity of traditional auscultation.

The procedure consists of three phases:

• Baseline Phase: Continuous 30-minute recording of bowel sounds to establish a physiological reference.
• Intervention Phase: Simultaneous 20-minute recording during EA. Sterile needles (0.30×40mm) are inserted into NP82 and SP15 points until "De Qi" sensation is achieved. Stimulation utilizes a dense-disperse wave at a 10 Hz frequency, with intensity adjusted (0.1-1 mA) based on participant tolerance.
• Post-intervention Phase: Continuous 30-minute recording after needle removal to evaluate sustained effects.

Data Analysis:

The primary quantitative variable is the Bowel Sound Interval (SSI), defined as the time between bowel sound events. Statistical analysis will be performed using Stata 17.0, employing Paired t-tests or Wilcoxon signed-rank tests to compare bowel sound frequencies across the three phases with a significance level of p < 0.05.

Inclusion criteria

• Healthy volunteers aged 18 years and older.
• No symptoms related to constipation after comprehensive evaluation based on Rome IV criteria.
• No gastrointestinal symptoms (abdominal pain, diarrhea, blood in stool, constipation, or bloating) in the 4 weeks prior to study participation.
• No use of medications that promote or inhibit bowel motility in the 4 weeks prior to participation (including prokinetics, laxatives, antispasmodics, or opioids).
• Fasting for at least 4 hours before the study session.
• No mental or intellectual disorders; capable of understanding the acupuncture and assessment procedures.
• Willingness to participate and signed informed consent form.

Exclusion criteria

• Participants with severe medical conditions (heart, brain, liver, kidney, hematological system, infectious diseases, cancer, or psychiatric disorders).
• Metabolic or functional disorders such as irritable bowel syndrome (IBS), thyroid dysfunction, or glucose/lipid metabolism disorders.
• Use of bowel motility-altering medications within the 4 weeks prior to participation.
• Participation in other clinical trials within the last 2 months.
• Received acupuncture treatment within the last month.
• Skin ulcers, abscesses, or infections at the acupuncture sites.
• Known metal allergy or severe needle phobia.