The Effect Of Acupuncture On Proximal Gastric Motility, Visceral Sensitivity, Electrogastrogram And Autonomic Nervous Function In Patients With Functional Dyspepsia

Objective: The mechanism of functional dyspepsia is unclear. Recently, Most studies show to be associated with gastric motility dysfunction, visceral hypersensitivity, gastric acid secretion, H. pylori infection, gut hormone, psychosocial and social environmental factors. Acupuncture shows better effect on treating functional dyspepsia in some clinical reports. This study was designed to observe the effect of acupuncture on proximal gastric motility, visceral sensitivity, electrogastrogram and autonomic nervous function in patients with functional dyspepsia using barostat by mechanic isovolumetric distensions. We proposed to investigate the acupuncture efficacy and mechanism, and provide clinical evidence for the treatment of functional dyspepsia patients by acupuncture.Methods:Study subjects choice: In the first and second protocol, sixty volunteers FD patients from the outpatient clinic were randomly divided into un-acupuncture group (n=30) and acupuncture group (n=30) according to the designed random table. In the third and fourth protocol, twenty volunteers FD patients from the outpatient clinic were randomly divided into un-acupuncture group (n=20) and acupuncture group (n=20) according to the designed random table. Twenty healthy volunteers were recruited for participation in the study for normal group. All patients fulfilled the new Rome II criteria of FD. Two weeks before study, each patient underwent endoscopy to rule out organic disease. Laboratory test, routine biochemistry, and abdominal ultrasound were also performed to exclude gallbladder and pancreatic disease, endocrine disease, and systemic diseases. No evidence of serious heart and renal inadequacy. No history of abdominal surgery. Females were required to have negative pregnancy test. Drugs known to affect GI motility had to be stopped at least 1week before the study. Informed consent was obtained from each participant. Before study, all subjects were in an overnight fast state at least 12 hours. For patients of acupuncture group, Zusanli (ST36) and Neiguan (PC6) were punctured and stimulated with an electric pulse generator by setting the parameters being 10mA in strength, 500s in the duration of pulses, 40Hz in frequency, 12cpm of pulse trains. Tianshu (ST25) was punctured with the needle retained. Acupuncture was not performed in un-acupuncture group and normal group. Isovolumetric gastric distention was performed in all the subjects. In first and second protocol, the initial and maximal tolerable volume and pressure of the stomach was recorded. Symptom scores of the epigastric pain, fullness and Nausea or vomiting were calculated during 200ml, 300ml and 400ml of gastric dilatation volumes. In third and fourth protocol, EGG and ECG was recorded at baseline, before and after acupuncture for 15min respectively. The automatic nervous function was assessed by the power spectral analysis of HRV. The heart rate variability (HRV) analysis parameters consist of the power in high frequency band (HF), the power in low frequency band (LF), the power in very low frequency band (VLF), and low power/high power (L/H). The EGG parameters include dominant frequency (DF), dominant power (DP), the instability coefficient of dominant frequency (DFIC), and percentage of normal gastric slow (N%). All data are expressed as mean±SD. Statistical significance was assigned at P≤0.05. Analysis was performed with SPSS12.0 computer software.Results:1. The effect of acupuncture on visceral sensitivity1.1 symptoms scoreDuring 200ml, 300ml and 400ml of gastric dilatation volumes, the symptom scores of the epigastric pain, fullness and Nausea or vomiting were all significantly higher in un-acupuncture group compared to normal group, and significantly higher compared to acupuncture group. There was no significant difference between normal group and acupuncture group.1.2 Initial pressure and volumeThe initial pressure and volume were all significant lower in un-acupuncture group compared to the normal group (6.40±2.41mmHg vs 8.82±2.65mmHg, P<0.05; 302.01±39.31ml vs 510.21±52.71ml, P<0.05), and also lower compared to the acupuncture group (6.40±2.41mmHg vs 8.06±2.95mmHg, P<0.05; 302.01±39.31ml vs 560.91±63.51ml, P<0.05). There was no significant difference between the acupuncture group and the normal group(P>0.05).1.3 Maximal pressure and volumeThe maximal pressure and volume were all significant lower in un-acupuncture group compared to the normal group (9.21±1.51mmHg vs 14.56±1.96 mmHg, P<0.05; 420.12±59.61ml vs 852.51±68.61ml, P<0.05), and also lower compared to the acupuncture group (9.21±1.51 mmHg vs 13.25±1.21 mmHg, P<0.05; 420.12±59.61ml ml vs 810.71±60.61ml, P<0.05).There was no significant difference between the acupuncture group and the normal group(P>0.05).2 The effect of acupuncture on proximal gastric motility2.1 Minimal Distending PressureThe minimal distending pressure was similar among the acupuncture group and un-acupuncture group and normal group. The mean minimal distending pressure was 5.28±1.61mmHg in acupuncture group and 4.98±1.81mmHg in un-acupuncture group and 5.76±1.91mmHg in normal group(P>0.05).2.2 ComplianceThe compliance in acupuncture group was 61.18±18.61mL/ mmHg, 51.44±17.81ml/ mmHg in un-acupuncture group, and 64.18±15.62mL/ mmHg in normal group. There was no significant difference between normal group and acupuncture group (P>0.05). the compliance was significantly lower in un-acupuncture group compared to the acupuncture group(P<0.05), and also lower compared to the normal group(P<0.05).3. The effect of acupuncture on gastric myoelectrical activity 3.1 The dominant frequency (DF)In acupuncture group, after acupuncture, the DF (3.08±0.28cpm) was significantly increased compared to the DF (2.42±0.21cpm) in the first 15min before acupuncture (P < 0.05). In un-acupuncture group, there was no significant difference between the first 15min (2.45±0.19cpm) and second 15min (2.43±0.22cpm) during the state of maximal tolerance volume dilatation(P>0.05).3.2 The percentage of normal slow waves (N%)In acupuncture group, after acupuncture, the N% (62.22±10.36%) was significant higher compared to the N% (40.78±8.67%) in the first 15min during the maximal tolerance state before acupuncture(P < 0.05) . In un-acupuncture group, there was no significant difference between the first 15min(42.45±8.36%) and second 15min(43.23±8.42%) during the state of maximal tolerance volume dilatation(P>0.05).3.3 The dominant power (DP)In acupuncture group, the DP was increased from 28.71±2.85 dB in baseline to 33.25±3.76 dB in the maximal tolerance state, and continue increased to 40.89±3.92 dB after acupuncture. The DP after acupuncture was significant higher compared to the baseline (P < 0.05). In un-acupuncture group, there was no significant difference between the first 15min (32.42±3.35) and second 15min (31.23±3.52) during the state of maximal tolerance volume dilatation(P>0.05).3.4 The instability coefficient of dominant frequency (DFIC)In acupuncture group, the DFIC was in maximal tolerance state before acupuncture (0.52±0.08) and after acupuncture( 0.37±0.04) respectively. The DFIC showed significant difference significant difference between the maximal tolerance state before acupuncture and after acupuncture (P < 0.05). In un-acupuncture group, there was no significant difference between the first 15min (0.54±0.07) and second 15min (0.55±0.08) during the state of maximal tolerance volume dilatation(P>0.05).4. Effect on Heart Rate Variability (HRV) 4.1 HFIn acupuncture group, the HF (614.19±279.70 ms2) after acupuncture was significant higher compared to the HF (380.20±214.78 ms2) during the maximal tolerance state before acupuncture(P < 0.05). In un-acupuncture group, there was no significant difference between the first 15min (374.29±235.41 ms2) and second 15min (371.90±245.21 ms2) during the state of maximal tolerance volume dilatation (P>0.05).4.2 LFIn acupuncture group, the LF was increased from 643.29±469.75 ms2 in baseline to 778.19±435.31ms2in the maximal tolerance state, and then decreased to 692.90±395.29 ms2after acupuncture. There was no significant difference among the LF in baseline and in the maximal tolerance state before and after acupuncture (P>0.05). In un-acupuncture group, there was no significant difference between the first 15min (774.09±315.42 ms2)and second 15min(771.65±343.24 ms2) during the state of maximal tolerance volume dilatation(P>0.05).4.3 VLFIn acupuncture group, after acupuncture, the VLF (1253.3±626.7ms2) was significant lower compared to the VLF (1946.5±962.0ms2) during the maximal tolerance state before acupuncture(P < 0.05). In un-acupuncture group, there was no significant difference between the first 15min (1879.3±935.4 ms2)and second 15min(1876.9±945.8ms2) during the state of maximal tolerance volume dilatation(P>0.05).4.4 L/HIn acupuncture group, the L/H was increased from 1.14±0.99 in baseline to 2.95±1.0 in the maximal tolerance state, and then decreased to 1.45±0.8 after acupuncture. The L/H was significant higher in the maximal tolerance state before acupuncture compared to the baseline (P<0.05). After acupuncture, The L/H was significant lower compared to the maximal tolerance state before acupuncture (P<0.05). In un-acupuncture group, there was no significant difference between the first 15min (2.93±1.1)and second 15min(2.91±0.9) during the state of maximal tolerance volume dilatation(P>0.05).Conclusions:1. Functional dyspepsia patients have lower initial and maximal tolerable thresholds, and acupuncture significantly lower the perception and discomfort thresholds induced by gastric distension.2. Functional dyspepsia patients have lower gastric compliance, and acupuncture has the ability to improve the gastric compliance in FD patients.3. Acupuncture could increase the percentage of normal waves in FD patients, increase the dominant power, decrease the instability coefficient of dominant frequency, and normalized gastric myoelectrical activity. Therefore promote gastric motility.4 Acupuncture could increase vagal nervous tone, decrease the LF/HF ratio, and change the balance between sympathetic activity and vagal activity. In conclusion, acupuncture could lower the visceral sensitivity of FD patients, promote gastric motility, normalized gastric myoelectrical activity, and improve the vagal tone. The mechanism of acupuncture in treating FD patients may be associated with many factors.