| ObjectMost of clinical and animal studies suggest that acupuncture has an effect of dual-directional regulation on gastrointestinal motility. There are preonunced effects of acupuncture on the treatment of various functional gastrointestinal disorders. However, the exact mechanism remains unclear for Dual effects of acupuncture on gastrointestinal motility.Interdigestive migrating motor complex (MMC), which is an inherent characteristic movement patterns in human and mammal’s gastrointestinal tract in the fasting state, is thought to be a specific index of reflecting gastrointestinal motility conditions.Based on the preliminary studies, Electromyography (EMG) and mechanical motilities were recorded by implanted electrode in the intestinal smooth muscle and sutured strain gauge sensors on the serosal surface of the normal and detached jejunum in anesthetized rats. Acupuncture was applied at ST37, LI11, ST25and BL25on different phases I, II and III of MMC respectively to explore the effect on EMG and mechanical motilities during different phases in normal and detached Jejunum rats respectly.Materials and MethodsSixteen healthy adult male Sprague-Dawley rats were used, weighing between250to300g. After an18h fast (with free access to water), rats were anesthetized with an intraperitoneal injection of10%urethane(1.0-1.2g/kg). A median abdominal incision (2-3cm) was made on surgical supine position. Then a strain gauge sensors was sutured on the smooth muscle serosal surface of the jejunum (10cm downstream from the Tretz Ligament) to record circular muscle contractions in anesthetized rats. The wires from the transducers were connected with the recording system. At the same time, one pair of bipolar platinum electrodes were implanted in the intestinal smooth muscle in Jejunum in anesthetized rats. The electrodes were connected to Powerlab8/20polygraph. The EMG and mechanical motilities were recorded by AD Instruments after Surgery. Acupuncture was carried on after two to three complete MMC Cycles were recorded about an hour later.Methods of detached Jejunum model:A detached surgery was operated on Jejunum (5cm proximal to the pylorus) with intact mesentery. A saline gauze was covered with detached Jejunum cross-sections. There was a recording of basic EMG and mechanical motilities after the detached surgery. Acupuncture was carried on after mechanical motilities recover to a stable condition.Acupoints positioning and Acupuncture operation: ST37(Shang ju xu),5mm lateral to anterior tubercle of the tibia and15mm below; LI11(Qu chi).locates in the midpoint between the lateral end of the transverse cubical crease and the lateral epicondyle of the humerus, inserting to a depth of4mm; ST25(Tian shu),2mm lateral to anterior median line, on the level of the navel, inserting to a depth of about5mm; BL25(Da chang shu), locates in the waist,5mm lateral to posterior midline under the fourth lumbar spines, inserting to a depth of about4mm. The needle was rotated clockwise and anti-clockwise for60s at2Hz at each acupoint.Statistical analysisStatistical analysis was performed with SPSS software for Windows,version19.0. All data were expressed as a mean±SD. Mean values were compared using the paired t test to compare the intestinal motility before and after acupuncture. The difference was considered significant at P<0.05.Signals of EMG and mechanical motilities were analyzed through Chart7.0software. The frequency (times/min) and amplitude (mv) of fast wave and slow wave were included in EMG analysis factors. The frequency (times/min) and amplitude (g) of contraction wave were included in mechanical motilities analysis factors. Statistical analysis was performed with SPSS software version19.0for Windows. All experiment data was expressed as a mean±SD. Mean values were compared using the paired T test to compare EMG and mechanical motilities before and after acupuncture. The difference was considered significant at P<0.05.Results1Effect of acupuncture at different acupoints on normal jejunum Electromyography (EMG) and Mechanical Motility during different MMC Phases in Anesthetized Rats1.1Effect of acupuncture at different acupoints on normal jejunum Electromyography(EMG) and Mechanical Motility during MMC Ⅰ Phases in Anesthetized RatsNo EMG fast wave during MMC Ⅰ Phases. There was no significant change (P>0.05,P>0.05) in the frequency and amplitude of jejunum EMG fast wave after acupuncture at ST37, LI11, ST25and BL25acupoints.For EMG slow wave, acupuncture at either ST37or LI11increased the frequency (P<0.01, P<0.05) and amplitude(P<0.01, P<0.01) of jejunum EMG slow wave significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG slow wave significantly. Acupuncture at BL25had no significant effect (P>0.05,P>0.05) on the frequency and amplitude of jejunum EMG slow wave significantly.For mechanical motilities, acupuncture at either ST37or LI11increased the frequency (P<0.05, P<0.05) and amplitude (P<0.01, P<0.01) of mechanical motilities in jejunum significantly;whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of mechanical motilities in jejunum significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of mechanical motilities in jejunum significantly.1.2Effect of acupuncture at different acupoints on normal jejunum Electromyography (EMG) and mechanical motility during MMC Ⅱ Phases in Anesthetized RatsDuring MMC Ⅱ Phases,for EMG fast wave, acupuncture at either ST37or LI11increased the frequency (P<.001, P<0.05) and amplitude (P<0.01, P(0.01) of jejunum EMG fast wave significantly;whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG fast wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG fast wave significantly.For EMG slow wave, acupuncture at either ST37or LI11increased the frequency (P<0.01,P<0.05) and amplitude (P<0.01, P<0.05) of jejunum EMG slow wave significantly;whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG slow wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG slow wave significantly.For mechanical motilities, acupuncture at either ST37or LI11increased the frequency (P<0.01, P<0.05) and amplitude (P<0.01, P<0.01) of mechanical motilities in jejunum significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of mechanical motilities in jejunum significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of mechanical motilities in jejunum significantly.1.3Effect of acupuncture at different acupoints on normal jejunum Electromyography (EMG) and mechanical motility during MMC III Phases in Anesthetized RatsDuring MMC III Phases,for EMG fast wave,acupuncture at either ST37or LI11increased the frequency (P<0.05, P<0.01) and amplitude (P<0.01, P<0.01) of jejunum EMG fast wave significantly;whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG fast wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG fast wave significantly.For EMG slow wave, acupuncture at either ST37or LI11increased the frequency (P<0.01, P<0.01) and amplitude (P<0.01, P<0.01) of jejunum EMG slow wave significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG slow wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG slow wave significantly.For mechanical motilities,acupuncture at either ST37or LI11increased the frequency (P<0.05,P<0.05) and amplitude (P<0.01, P<0.01) of mechanical motilities in jejunum significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of mechanical motilities in jejunum significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of mechanical motilities in jejunum significantly.2Effect of Acupuncture at different acupoints on detached jejunum Electromyography (EMG) and mechanical motility during different MMC Phases in Anesthetized Rats2.1Effect of acupuncture at different acupoints on detached jejunum Electromyography (EMG)and mechanical motility during MMC Ⅰ Phases in Anesthetized RatsNo EMG fast wave still during MMC I Phases after the surgery of detached Jejunum. There was no significant change (P>0.05, P>0.05) in the frequency and amplitude of jejunum EMG fast wave after acupuncture at ST37, LI11, ST25and BL25acupoints.For EMG slow wave, acupuncture at either ST37or LI11increased the frequency (P<0.05, P<0.05) and amplitude(P<0.01, P<0.01) of jejunum EMG slow wave significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG slow wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG slow wave significantly.For mechanical motilities, acupuncture at either ST37or LI11increased the frequency (P<0.05, P<0.05) and amplitude (P<0.05, P<0.05) of mechanical motilities in jejunum significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of mechanical motilities in jejunum significantly. Acupuncture at BL25had no significant effect (P>0.05,P>0.05) on the frequency and amplitude of mechanical motilities in jejunum significantly.2.2Effect of acupuncture at different acupoints on detached jejunum Electromyography (EMG) and mechanical motility during MMC Ⅱ-Ⅲ Phases in Anesthetized RatsDuring MMC Ⅱ-Ⅲ Phases, for EMG fast wave, acupuncture at either ST37or LI11increased the frequency (P<0.05,P<0.01) and amplitude (P<0.05, P<0.05) of jejunum EMG fast wave significantly; whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG fast wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG fast wave significantly.For EMG slow wave,during MMC Ⅱ-Ⅲ Phases, acupuncture at either ST37or LI11increased the frequency (P<0.05,P<0.05) and amplitude (P<0.01,P<0.01) of jejunum EMG slow wave significantly, whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of jejunum EMG slow wave significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of jejunum EMG slow wave significantly.For mechanical motilities, during MMC Ⅱ-Ⅲ Phases, acupuncture at either ST37or LI11increased the frequency (P<0.05,P<0.05) and amplitude(P<0.001,P<0.01)of mechanical motilities in jejunum significantly, whereas acupuncture at ST25decreased the frequency (P<0.01) and amplitude (P<0.01) of mechanical motilities in jejunum significantly. Acupuncture at BL25had no significant effect (P>0.05, P>0.05) on the frequency and amplitude of mechanical motilities in jejunum significantly. ConclusionsThis study systematically investigated the effects of acupuncture at different acupoints on normal and detached jejunum Electromyography (EMG) and mechanical motility during MMC phases in anesthetized rats. We make the following conclusions according to the above results:(1)Acupuncture at heterotopic acupoints (ST37or LI11) has exciting effects on EMG and mechanical Motility during MMC phases in normal and detached Jejunum.(2)Acupuncture at homotopic acupoints ST25always produces inhibition effect on EMG and mechanical Motility during MMC phases in normal and detached Jejunum.(3)The effects of acupuncture at different acupoints on jejunum EMG and mechanical motility during MMC phases are different which are related to both stimulation acupoint and the segment innervation of gastrointestinal organ.(4)Dual-directional regulation effect of acupuncture depends on the acupoint specific biological characteristic. Heterotopic acupoints (ST37or LI11) mainly produce exciting effect on Jejunum mechanical motility, whereas homotopic acupoints (ST25) mainly produce inhibition effect on jejunum mechanical motility. The inhibitory effects of acupuncture at homotopic acupoint ST25and exciting effects of acupuncture at heterotopic acupoints ST37or LI11on jejnum mechanical motility are independent of intestinal movement, which are associated with acupoints characteristics. |
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