| Objectives:1. To observe the effects of Chinese medicinal glycyrrhiza on the gastric residual rateand the intestinal propulsive rate of rat models of low gastric motility, which areestablished by utilizing glycyrrhiza;2. To observe the effects of areca on the gastric residual rate and the intestinalpropulsive rate of rats with low gastric motility, to determine the gastrichalf-emptying time (GET1/2) by using SPECT (Single Photon Emission ComputedTomography), and to observe the effects of the areca on the gastric motility;3. To observe the effects of the areca on changing the ultrastructure of interstitial cellsof Cajal (ICC) and the relationship between the ICC with the peripheral entericnervous system by using a transmission electron microscope (TEM), and to explorethe effects of the areca on the expression of c-kit in gastric tissues of model rats byusing an immunohistochemistrical method.4. To analyze components of the areca by adopting HPLC (High Performance LiquidChromatography) and LC-MS (Liquid Chromatography-Mass Spectrometry) andextract effective components of the areca in order to observe the effects of theeffective components on contraction of in-vitro gastric smooth muscle cells.Methods:1. Establishment of rat models of low gastric motilityRaw glycyrrhiza solutions are prepared and divided into five dose groups, namely, 2.5g/kg,5g/kg,7.5g/kg,10g/kg and15g/kg. Rats are continuously fed with the rawglycyrrhiza solutions by gavage for5days. The gastric residual rate is measured byusing an ultraviolet spectrophotometer through pH-sensitive assay using phenol red,and the intestinal propulsive rate is measured and calculated. The GET1/2of99mTc-MIBI (Technetium-Methoxy Isobutyl Isonitrile) solution in rat stomachs in allgroups is detected by using SPECT.2. Effects of the areca on the gastric motilityBy taking mosapride as a control medicine, the rat models of low gastric motility,established by adopting the method1, are divided into a model group (10g/kgglycyrrhiza), a normal control group (0.9%NaCl), a western medicine group(0.4mg/kg mosapride) and an areca group (10k/kg areca), and are fed by gavage for7days. The gastric residual rate, the intestinal propulsive rate and the GET1/2of therats in each group are measured.3. Effects of the areca on the ultrastructure of intragastric ICC and the expression ofc-kitModels and groups are established according to the methods1and2. A wholestomach is removed, and two pieces of tissues are taken from each of the gastricfundus, the gastric body and the gastric antrum. One piece of each kind of tissue isused for making an ultrathin section to be observed and recorded by the TEM, and theother piece of each kind of tissue is used for making an immunohistochemistricalspecimen for observation of c-kit antibody expression and calculation of positive cellareas.4. Extraction of areca effective components and effects of the areca effectivecomponents on in-vitro smooth muscleLyophilized areca powder is prepared, smooth muscle strips of guinea pigs are made,and the effects of extractives of different batches on the muscle strips are observed; the areca extractives of effective batches are selected, the ultraviolet absorptionspectra of the selected extractives are recorded by means of HPLC, and the effectivecomponents of the selected extractives are extracted; and the effects of the effectivecomponents on the contraction of the in-vitro smooth muscle of the guinea pigs areobserved, and a mechanism is analyzed.Results:1. According to the gavage using the glycyrrhiza solutions with different doses(2.5g/kg,5g/kg,7.5g/kg,10g/kg and15g/kg), the gastric residual rate in the group of10g/kg dose is higher than that in other groups and is significantly higher than that inthe normal control group (P<0.01), and the GET1/2is prolonged (P<0.05). Whilecomparing the intestinal propulsive rate in the group of5k/kg dose with that in thenormal control group, a statistical significance can be achieved (P<0.05).2. Compared with the normal control group, in the areca group and the westernmedicine group, the gastric residual rate is decreased (P<0.05), the GET1/2isshortened, and the intestinal propulsive rate is increased; meanwhile, the gastricresidual rate in the model group is significantly higher (P<0.05), and the GET1/2isprolonged. No statistical differences are presented between the areca group and themosapride group.3. According to TEM-based observations, the shapes of the ICC in the rat stomachs ofthe model group are more flat, or even irregular, and the protrusions of the ICCbecome shot and small; and the ICC in the rats of the other three groups take theshape of a spindle, with huge oval nuclear cores and long protrusions extendingoutwards, and the cytoplasm of the ICC are rich in mitochondria, smoothendoplasmic reticulum and rough endoplasmic reticulum based on observations of25,000×magnification. The connection between the ICC and the surrounding intestinal neurons axoaxonic synapse is increased in the areca group. In the fourgroups, the intragastric positive expression of the c-kit in the gastric antrum is highestand is higher than that in the gastric body and the gastric fundus. The positiveexpression area of the c-kit in the areca group is highest, particularly in the gastricantrum (79,700±3,900μm2).4. The lyophilized areca powder of ten batches is respectively used for performingguinea pig in-vitro smooth muscle experiments. The lyophilized areca powder of thebatches1and2are selected to undergo HPLC component analysis, and69peakvalues are shown on the ultraviolet absorption spectrum, wherein the34th and42thpeak value are higher. The component corresponding to the34th and42th peak valueis extracted, and10μmol/L of dose BL42is found to have the strongest effect on thecontraction of the gastric circular muscle and the gastric longitudinal muscle of thesmooth muscle, and the areas under a curve are respectively5.96±0.585g/s and5.64±0.52g/s, which approaches anAch (Acetylcholine) effect.Conclusion1. When the dose is10g/kg, the glycyrrhiza has the effects of increasing the gastricresidual rate and prolonging the GET1/2for the rats, thus, the glycyrrhiza can beused for establishing the rat models of low gastric motility.2. The areca has the effects of lowering the gastric residual rate, shortening the GET1/2and increasing the intestinal propulsive rate for the rat models of low gastricmotility, thus, the areca is proved to have the effect on promoting the gastric motility.3. The areca has the effects of enhancing the relationship between intragastric ICC ofrats of low gastric motility and the peripheral enteric nervous system, and enlargingthe positive expression area of c-kit in the gastric antrum, the gastric body and thegastric fundus, thus, a certain relationship is presented between the gastric motility promotion effect of the areca and ICC.4. BL34and BL42prepared by means of HPLC has a stronger effect on thecontraction of the in-vitro smooth muscle of the guinea pig, and is similar to Ach, andthe components of BL34and BL42need further experimental studies. |
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